Plan discontinued for 2027 · Mesa County, Colorado

Can I Change My Medicare Advantage Plan After December 7?

If your plan is being discontinued, yes. Medicare gives you a Special Enrollment Period from December 8 through the last day of February. What nobody prints on the letter is the start-date rule: enroll by December 31 and your new coverage begins January 1. Enroll in January or February and you spend a month or two in Original Medicare with no drug plan first.

Medicare On Main Data Desk

Published September 19, 2026 · 9 min read · Reviewed by Brian Penner, 22+ years in Medicare

Every January somebody calls our Grand Junction office with the same sentence: "I think I missed it." The letter came in October, the holidays happened, and now the old plan's card does not work at the pharmacy. Often the caller has more room than they think. Other times they are a few weeks into a gap that one phone call in December would have closed. The difference between those two callers is almost never December 7. It is whether they knew which window they were standing in, and what day the new coverage would actually begin.

What December 7 actually closes

Medicare.gov's Open Enrollment page is precise about it: "Open Enrollment happens from October 15 – December 7," and changes "are effective January 1 of next year (the plan must get your enrollment request by December 7)." That is the general window, open to everybody on Medicare whether or not anything happened to their plan. When it closes, a person whose plan is continuing is settled for the year, apart from the January–March period described below.

A person whose plan is being discontinued is in a different position. Federal regulation 42 CFR § 422.62(b)(1) lets an individual change an election outside the annual period when the organization "has notified the individual of the impending termination of the plan, or the impending discontinuation of the plan in the area in which the individual resides." Medicare.gov's Special Enrollment Periods page gives the dates in plain English: "Between December 8 and the last day in February of the following year." The Plan Non-Renewal Notice is what proves you qualify. Keep it.

The same enrollment, filed on four different days

The window is twelve weeks long, and the weeks are not equal. The start-date rule is in 42 CFR § 422.68(d): for a special election period, coverage "is effective the first day of the calendar month following the month in which the election is made, unless otherwise noted." Lay that rule over the calendar and you get this.

Sources: Medicare.gov, Open Enrollment; Medicare.gov, Special Enrollment Periods; 42 CFR § 422.68(b) and (d). Start dates are the regulation's general rule applied to the 2026–2027 calendar; confirm your own effective date with the plan when you enroll.

The second row is the one I wish were printed on the letter. A Mesa County reader who misses December 7 by a week has lost nothing but a little calm. An application the plan receives on December 15 is a December election, and a December election starts January 1, the same day an October enrollment would have. The old plan's coverage ends at midnight on December 31, the new one picks up, and there is no month in between. What changes on January 1 is not the window. It is the price of using it.

What you actually have during the gap

You are never uninsured. Medicare.gov states the default in one sentence: "You'll be enrolled in Original Medicare if you don't join another Medicare Advantage Plan before your current plan ends." Part A and Part B keep working, and Original Medicare has no network, so any provider that accepts Medicare can see you. Three things are missing, though, for as long as the gap lasts.

• Prescription coverage. Original Medicare does not include Part D. Unless you separately joined a stand-alone drug plan, January prescriptions are at the pharmacy's cash price. A new plan that starts February 1 does not reach back to pay for them.
• A ceiling. Medicare Advantage plans set a yearly limit on what you pay for covered services. Original Medicare on its own does not. You owe the Part B deductible ($283 in 2026; the 2027 amount is announced by CMS in the fall) and then generally 20% of Part B services, with no cap.
• The extras. Dental, vision, hearing and similar benefits that came with the old plan stop on December 31 and resume only when a new plan that offers them begins.

For a healthy person, one month of that is usually an inconvenience. For someone managing a chronic condition it is a real bill. CDC PLACES puts high blood pressure at 26.6% of Mesa County adults and diabetes at 8.1% (2023). Those are households that fill prescriptions every month, including January. Our post on what happens if you don't pick a new plan prices the default in detail; the point here is narrower. The gap is optional through December 31, and it gets longer by exactly one month each time the calendar turns.

One more clock is worth knowing about. CMS's late enrollment penalty rules look at stretches of 63 days or more in a row without Part D or other creditable drug coverage. A person who defaults on January 1 and enrolls in late February for a March 1 start has gone 59 days. That is inside the line, but not by much, and it is one more reason the February end of this window is not a place to plan on being.

Who gets which door after December 7

Most of the confusion in January comes from people applying one group's rules to another group. The non-renewal window is generous, and it is also narrow: it belongs to the person whose plan is leaving, and to nobody else in the house or on the street.

Sources: Medicare.gov, Special Enrollment Periods; Medicare.gov, Joining a plan; 42 CFR § 422.62(a)(3) and (b)(1); Medicare.gov, When can I buy a Medigap policy?. No 2027 plan, carrier or star rating is stated; CMS publishes the 2027 landscape on October 1 and the star ratings in October.

If you are not sure which row you are in, the mail tells you. A Plan Non-Renewal Notice says the plan will not be offered where you live next year, and Medicare.gov's description of it is blunt: "You must look for a new plan for coverage next year." An Annual Notice of Change says the plan is staying and lists what is different. Our first-steps post shows how to tell the two apart in about a minute.

The January–March period is a different tool

People mix these two up constantly, so it is worth putting them side by side. The Medicare Advantage Open Enrollment Period runs January 1 – March 31. 42 CFR § 422.62(a)(3) says "an individual who is enrolled in an MA plan may make an election once during the first 3 months of the year to enroll in another MA plan or disenroll to obtain Original Medicare." Medicare.gov's joining-a-plan page adds the condition in parentheses, "only if you're already in a Medicare Advantage Plan," and the start date: "First of the month after the plan gets your request."

Two consequences follow. First, a person who did nothing and landed in Original Medicare on January 1 cannot use it, because they are no longer in an Advantage plan. Their door is the non-renewal Special Enrollment Period, and it closes a month earlier, on February 28. Second, a person who enrolled in a new Advantage plan in December and discovers in January that a specialist is not in the network after all does have it. That one change, through March 31, is the second look the rules allow. It is a good reason to check the 2027 network by name before you enroll, and a fair backstop if something was missed.

If you are thinking about Medigap, watch both clocks

A discontinued plan opens a second, separate right. Medicare.gov's Medigap tool says a person whose Medicare Advantage plan is leaving Medicare can buy certain Medigap plans "if you switch to Original Medicare," applying as early as "60 days before the date your Medicare Advantage Plan coverage ends" and "no more than 63 days after." For a December 31, 2026 end date, that last day is March 4, 2027 by our count. Do the arithmetic from your own end date.

The two windows close four days apart, and they pull in opposite directions. Using the Special Enrollment Period to join another Advantage plan ends the Medigap right, because the right exists only for someone who goes to Original Medicare. Staying in Original Medicare to use the Medigap right still leaves you needing a stand-alone drug plan, and the same December 8 through February window is how you join one. A person who wants a Medigap policy and a drug plan to begin together on January 1 should have both applications in during December. Colorado's plan letters and exclusions are in our Medigap guaranteed-issue post.

The 5-star window, briefly

There is one more after-December-7 door that has nothing to do with a discontinuation. Medicare.gov lets anyone who lives "in the service area of one or more Medicare Advantage Plans or Medicare drug plans with an overall quality rating of 5 stars" join such a plan "one time between December 8 of the year before the plan year and November 30 of the plan year." Whether that matters on the Western Slope depends on the 2027 star ratings, which Medicare publishes in October. We will not guess at them. When they are out, Medicare Plan Finder shows each plan's rating next to its name.

What I would actually do

• Treat December 7 as the goal and December 31 as the wall. Open Enrollment is the calm path. You compare plans in October with the full 2027 data in front of you, and you are done. If life gets in the way, the last three weeks of December cost you nothing in coverage.
• Do not let it slide into January on purpose. Nothing about the plans gets better in January. The only thing that changes is that you start paying for prescriptions out of pocket.
• If you are already in the gap, move this week. An enrollment on January 30 and an enrollment on February 1 start a full month apart.
• Decide the Medigap question first. It determines whether you want another Advantage plan at all, and its clock ends on March 4, 2027.
• Keep the letter. It is your proof of the Special Enrollment Period and of the Medigap right.

The caller from the top of this article, the one who thought she had missed it, phoned on December 19. She had a non-renewal letter in a drawer and twelve days left in the year. We compared her doctors and her four prescriptions against the plans available to her, filed one enrollment, and her new coverage began January 1. Had she called three weeks later, the same enrollment would have started February 1, and January's prescriptions would have been hers to pay. Same person, same plan, same form. The calendar was the only difference.

How we know all this: the Medicare On Main Data Desk frames every article with public data. The December 8 through last-day-of-February Special Enrollment Period, its Original Medicare default, and the one-time 5-star window are quoted from Medicare.gov's Special Enrollment Periods page; the qualifying event from 42 CFR § 422.62(b)(1); the once-per-year January–March election for individuals "enrolled in an MA plan" from 42 CFR § 422.62(a)(3) and Medicare.gov's joining-a-plan page; the first-of-the-following-month effective date from 42 CFR § 422.68(d), and the January 1 effective date for Open Enrollment from § 422.68(b) and Medicare.gov; the 63 days Medigap application limit from Medicare.gov's Medigap tool, with March 4, 2027 computed from a December 31, 2026 end date; the 63-day Part D creditable-coverage rule from CMS; the $283 Part B deductible and $202.90 standard premium for 2026 from the CMS fact sheet of November 14, 2025; and Mesa County prevalence from CDC PLACES (2023). The December 19 caller is a composite, not a specific client. No 2027 plan, premium, carrier, network or star rating is stated, because CMS has not published them. This is education, not advice; confirm your plan, costs, and eligibility with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.