Grand Junction · Switching plans for 2027
Do I Need to Cancel My Old Medicare Plan Before Switching?
No, and calling to cancel first is the one way to turn a clean switch into a gap. Enrolling in the new plan is what ends the old one. The exceptions are short and worth knowing before October 15: a Medigap policy never cancels itself, leaving for Original Medicare without a drug plan takes a request, and retiree coverage can end for good. Here is what is automatic, what is not, and the order to do it in.
The bottom line
- Enrolling is the cancellation. CMS's 2027 guidance: a member who elects a new plan "will automatically be disenrolled from the old plan and enrolled in the new plan by CMS systems with no duplication or delay in coverage."
- The dates: enroll October 15 to December 7, 2026. The old plan covers you through December 31. The new one starts January 1, 2027.
- A Medigap policy is the exception. It is private insurance outside that system. Medicare.gov: "Contact your Medigap insurance company to cancel your Medigap policy," and "in most cases you won't be able to get it back."
- Leaving for Original Medicare takes one of two things: enrolling in a stand-alone Part D plan, which disenrolls you from the Advantage plan, or asking to be disenrolled through 1-800-MEDICARE or a signed notice to the plan.
- Changed your mind? The last enrollment the plans receive by December 7 is the one that counts, and an enrollment can be cancelled any time before it takes effect.
The instinct is a reasonable one. Everywhere else in life, you close the old account before you open the new one, or at least you tell somebody. Medicare plans work the other way around, and the reason is that you cannot hold two at once. Medicare.gov puts it in two sentences: "Your old drug coverage will end when your new drug coverage begins. You should get a letter from your new plan telling you when your coverage begins, so you don't need to cancel your old plan." The regulation behind it, 42 CFR § 422.66(b)(1), lists electing "a different MA plan" as the first of the two ways to leave the one you have.
In Mesa County that covers most people who will change anything this fall. Of the county's 41,709 Medicare beneficiaries in June 2026, 17,134 were in a Medicare Advantage plan with drug coverage and 15,944 were in a stand-alone Part D plan, according to the CMS monthly enrollment file. For both groups, a like-for-like switch is one action, not two.
What ends on its own, and what does not
| You have now | You are moving to | What happens to the old coverage | What you do |
|---|---|---|---|
| Medicare Advantage plan | A different Medicare Advantage plan | Ends on its own | Enroll in the new plan. Do not call the old one. |
| Stand-alone Part D drug plan | A different Part D drug plan | Ends on its own | Enroll in the new plan. Your Medigap policy, if you have one, is untouched. |
| Original Medicare with a Part D plan and a Medigap policy | A Medicare Advantage plan with drug coverage | Part D ends on its own. Medigap does not. | Decide about the Medigap policy on purpose, then contact the Medigap company yourself. It cannot pay Advantage plan costs, and in most cases you cannot get it back. |
| Medicare Advantage plan with drug coverage | Original Medicare with a Part D plan and a Medigap policy | Ends when the Part D plan starts | Apply for the Medigap policy first and wait for the answer. Then enroll in the Part D plan, which disenrolls you from the Advantage plan. |
| Medicare Advantage plan | Original Medicare with no Part D plan (drugs through the VA, for example) | Nothing is automatic | Ask to be disenrolled: call 1-800-MEDICARE, or mail or fax a signed notice to the plan. |
| A plan that is being discontinued for 2027 | Anything | Ends December 31 whatever you do | Nothing to cancel, but nothing starts unless you enroll in it. |
| Employer or retiree group coverage | An individual Medicare plan | May end, and may not come back | Call the benefits office before you enroll in anything. |
Sources: CMS CY 2027 Enrollment and Disenrollment Guidance, §§ 20.1, 30.8 and 60.1; 42 CFR § 422.66(b); § 423.36(a); Medicare.gov, switch or drop a Medigap policy; Medicare.gov, retiree insurance. The Part D row applies to Advantage HMOs and PPOs; Private Fee-for-Service plans without drug coverage and Medical Savings Account plans follow different rules.
The first two rows are the simple ones. The rest of this article is about the other five, because that is where the phone calls to our office come from.
Why cancelling first can backfire
Suppose you call your current Advantage plan on October 20 and ask to be disenrolled, planning to pick a new plan later. The guidance sets the effective date of a disenrollment made during Open Enrollment as "January 1 of the following year," so nothing happens right away and you are still covered through December. The problem is what the request means on January 1. The guidance again: "If an individual disenrolls through an MA organization or 1-800-MEDICARE, the individual will return to Original Medicare unless they elect a new MA plan."
Original Medicare on its own has no drug coverage and no yearly limit on what you pay. If the new enrollment you meant to make is late, incomplete, or never sent, that is where you are standing in January. On the drug side a clock starts too. Medicare.gov: "if you go 63 days or more in a row without other creditable prescription drug coverage," you will "have to wait for an enrollment period to sign up for coverage" and "may have to pay a late enrollment penalty." Enrolling in the new plan and letting the system handle the old one takes that risk off the table, because the old coverage cannot end unless the new coverage has been accepted.
There is a quieter version of the same mistake. Someone in an Advantage plan that includes drug coverage sees a Part D plan with a low premium and enrolls in it, thinking it adds to what they have. It does not add. The guidance's own table answers "No" to whether a member of an Advantage HMO or PPO can hold a separate stand-alone drug plan, and the enrollment does exactly what the rule says: members "will be disenrolled from that MA plan upon successful enrollment in a PDP." The doctor network and the out-of-pocket limit leave with it.
The Medigap policy: the one thing that never cancels itself
A Medicare Supplement policy is a private insurance contract between you and an insurance company. Medicare's enrollment system does not start it, and it does not stop it. If you join an Advantage plan for 2027 and do nothing else, the Medigap premium keeps drafting from your account in January, for a policy that, in Medicare.gov's words, "can't pay any Medicare Advantage Plan deductibles, copayments, coinsurance, or premiums."
That is an argument for making the decision deliberately, not for cancelling quickly. The same page warns: "Keep in mind that if you drop your Medigap policy, in most cases you won't be able to get it back, so pay attention to the timing." Colorado has no birthday rule or anniversary switching window, so someone who drops a Medigap policy at 72, tries an Advantage plan, and wants the policy back at 75 is usually filling out a health application. There is a federal trial right for a first-time Advantage member who returns within 12 months, and we walk through it in the Colorado Medigap rights post. It is a narrow door, and it closes.
The order reverses when you go the other direction. Moving from an Advantage plan to Original Medicare with a Medigap policy, the Medigap application comes first. Medicare.gov says an insurer may sell a policy to someone in an Advantage plan who is "switching back to Original Medicare," as long as "your plan coverage will end before the Medigap policy's effective date." So you apply, you wait for the company's answer, and only after you have it do you enroll in the Part D plan that ends the Advantage plan. Doing it in the other order can leave you in Original Medicare with a declined application and no way back into the Advantage plan until the next enrollment period.
Not sure which row of the table you are in?
Bring your current cards and any letters to our Grand Junction office, or call. We will tell you what ends on its own, what needs a phone call, and what order to do it in. Free, and nothing to sign. We do not offer every plan available in your area.
Book a coverage review →Leaving for Original Medicare without a drug plan
Some Grand Valley retirees get their prescriptions through the VA and want Original Medicare without a Part D plan. For them, no new enrollment exists to trigger the automatic step, so the Advantage plan has to be told. Section 60.1 of the guidance lists the ways: "Mailing or faxing a signed notice of disenrollment to the plan," the plan's own secure website if it has one, or "Calling 1-800-MEDICARE." It also lists what does not count: "Online disenrollment by other means, such as emailing the plan (including emailing an attachment of the signed notice of disenrollment) or via a broker website, are not permitted." Keep the confirmation letter the plan sends back.
Retiree and employer coverage: ask before you enroll
The automatic step is a convenience when you mean it and a hazard when you do not. People with retiree coverage from a former employer, a union or a public pension system are the ones most exposed. Medicare.gov: "Before you make any decisions, check with your retiree coverage to find out if you'll lose retiree coverage (including any non-drug health coverage) for yourself and/or your spouse or dependents if you get Medicare drug coverage." Whether a group plan lets you return after you leave is the group's rule, not Medicare's, and the answers differ. Make the call to the benefits office before the enrollment, because the enrollment is the part that cannot be talked back.
What if I change my mind after I enroll?
Two rules help here. The first is that Open Enrollment does not lock in your first choice. The guidance: "An individual can, in most situations, submit more than one enrollment request prior to the effective date. The last enrollment choice made, determined by plan receipt date, will be the choice that becomes effective." Enroll in one plan on October 16, find out on November 10 that your cardiologist is not in its 2027 network, enroll in a different one, and the second plan is the one that starts January 1. Medicare.gov adds the deadline: "the plan must get your request to join by December 7."
The second is that an enrollment can be withdrawn. Section 70.2 defines a cancellation as "an action taken by an individual to stop an enrollment or disenrollment request prior to the effective date," and adds that "an individual does not need an election period to request a cancellation." The guidance's example is a woman who enrolls in a new plan on November 12 and calls it on December 21 to say she wants to stay where she was; the new plan has to process the cancellation. You contact the plan you are backing out of, not the one you are keeping. After January 1 that option is gone, and someone in an Advantage plan is left with the January 1 to March 31 window, which allows one change.
If your plan is the one being discontinued
Then there is nothing to cancel. A plan that is not renewing for 2027 ends December 31 by its own terms, and a call to the plan changes nothing about that date. What the letter does change is your list of options, which is longer than usual: Open Enrollment through December 7, a Special Enrollment Period that runs from December 8 through the end of February, and a guaranteed-issue right to certain Medigap policies. It also changes the default. With an ordinary plan, doing nothing means you keep it. With a discontinued plan, doing nothing means Original Medicare with no drug plan on January 1. If you are not sure which kind of letter you are holding, start with the plan ID.
What I would do
Pick the new coverage first and enroll in it, and leave the old plan alone. Write down the confirmation number and the date. If a Medigap policy is involved in either direction, settle that part before anything else moves. Keep the old card in your wallet through December 31 and use it; the new card is good from January 1. Then look at your January bank statement or Social Security deposit and confirm that the old premium stopped and the new one, if there is one, started. If the old plan drafted your checking account, that is the one loose end I see most often, and one call to the old plan fixes it.
The reason to get the mechanics right is that the coverage matters more than the paperwork. In Mesa County, 26.6% of adults live with high blood pressure and 8.1% with diabetes, per CDC PLACES. Most of them fill a prescription every month, and a January without drug coverage is the outcome every rule in this article exists to prevent.
How we know all this: the Medicare On Main Data Desk frames every article with public data — here, the CMS CY 2027 Medicare Advantage and Part D Enrollment and Disenrollment Guidance (§§ 20.1, 30, 30.8, 60.1 and 70.2) for automatic disenrollment, the effective dates, the last-choice rule, the permitted disenrollment methods and cancellations; 42 CFR § 422.66(b) and § 423.36(a), quoted as published on Cornell LII; Medicare.gov's pages on switching drug coverage, joining a plan, dropping a Medigap policy, illegal Medigap practices and retiree insurance, quoted as published; the CMS Medicare Monthly Enrollment file for Mesa County (June 2026); and CDC PLACES county data (2023). No 2027 plan, premium or carrier is named, because CMS has not released the 2027 landscape. This is education, not advice; confirm your plan's rules with the plan, and plans, costs and eligibility with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.
Frequently asked questions
Do I need to cancel my old Medicare Advantage plan before enrolling in a new one?
No. CMS's 2027 enrollment guidance says that when you elect a new Medicare Advantage or Part D plan while still in a different one, you "will automatically be disenrolled from the old plan and enrolled in the new plan by CMS systems with no duplication or delay in coverage." Medicare.gov says the same thing in plainer words: "you don't need to cancel your old plan." Enroll in the new plan between October 15 to December 7, 2026, keep using the old card through December 31, and start using the new one January 1.
How do I cancel my Medicare Advantage plan?
There are four ways, and the first is the one most people should use: enroll in another plan during a valid enrollment period. The other three are for leaving without joining anything new: call 1-800-MEDICARE, mail or fax a signed notice to the plan, or use the plan's own secure website if it offers that. CMS's guidance says an emailed request, or one sent through a broker's website, is "not permitted." If you disenroll without choosing a new Advantage plan, you "will return to Original Medicare," with no drug coverage unless you add a Part D plan.
Can I cancel my Medicare Advantage plan at any time?
No. You can leave only during an enrollment period. The main one is Open Enrollment, October 15 to December 7, with the change taking effect January 1. People already in an Advantage plan get a second chance from January 1 to March 31, effective the first of the following month. Outside those, you need a Special Enrollment Period, such as a move or a plan that is ending. A request sent to the plan at any other time is denied, and you stay where you are.
Do I have to cancel my Medigap policy if I join a Medicare Advantage plan?
It does not cancel itself, so the decision is yours. Medicare.gov: "Your Medigap policy can't pay any Medicare Advantage Plan deductibles, copayments, coinsurance, or premiums, if you decide to keep your Medigap policy," and to end it you "Contact your Medigap insurance company to cancel your Medigap policy." The same page carries the warning that matters in Colorado: "if you drop your Medigap policy, in most cases you won't be able to get it back." Colorado has no birthday rule or anniversary switching window, so a later application is usually underwritten.
What happens if I enroll in two Medicare plans by mistake?
You end up in one. CMS's guidance: "An individual can, in most situations, submit more than one enrollment request prior to the effective date. The last enrollment choice made, determined by plan receipt date, will be the choice that becomes effective." So if you enrolled in one plan in October and a different one in November, the November plan is your 2027 plan. If that is not what you meant, you can cancel the later enrollment by contacting that plan before January 1, or enroll again by December 7.
Do I need to cancel a Medicare plan that is being discontinued?
No. A plan that is not renewing for 2027 ends on December 31 without any action from you. The risk runs the other way: nothing replaces it unless you enroll in something. If you do nothing, you are in Original Medicare on January 1 with no drug plan. You have Open Enrollment through December 7, a Special Enrollment Period from December 8 through the end of February, and a Medigap guaranteed-issue window from 60 days before to 63 days after the coverage ends.
Sources
- CMS — CY 2027 Medicare Advantage and Part D Enrollment and Disenrollment Guidance — "automatically be disenrolled from the old plan and enrolled in the new plan by CMS systems with no duplication or delay in coverage"; "January 1 of the following year"; "The last enrollment choice made"; the permitted disenrollment methods; cancellations.
- Medicare.gov — What if I want to switch, drop, or rejoin drug coverage? — "you don't need to cancel your old plan"; the 63-day rule.
- 42 CFR § 422.66 — Coordination of enrollment and disenrollment through MA organizations (Cornell LII) — "Elect a different MA plan" as a method of disenrollment.
- 42 CFR § 423.36 — Disenrollment process (Cornell LII) — "by enrolling in a different PDP plan."
- Medicare.gov — Joining a plan — October 15–December 7; "the plan must get your request to join by December 7"; the January 1–March 31 window.
- Medicare.gov — Can I switch or drop my Medigap policy? — "Contact your Medigap insurance company to cancel your Medigap policy"; "in most cases you won't be able to get it back."
- Medicare.gov — Illegal Medigap practices — "if your plan coverage will end before the Medigap policy's effective date."
- Medicare.gov — Retiree insurance — "check with your retiree coverage to find out if you'll lose retiree coverage."
- CMS Medicare Monthly Enrollment (data.cms.gov) — Mesa County, CO, June 2026 — 41,709 beneficiaries; 17,134 in Medicare Advantage plans with drug coverage; 15,944 in stand-alone Part D plans.
- CDC PLACES: Local Data for Better Health, County 2023 — Mesa County high blood pressure and diabetes prevalence.
