Generally, if you join a Medicare Advantage Plan or Medicare Prescription Drug Plan, you can only change plans from November 15 through December 31 of every year. This change will be effective January 1 of the following year.
If you are also eligible for Medicaid, you can switch plans at anytime.
(Primary Source: Centers for Medicare and Medicaid Services - Medicare and You Handbook 2007. This content may have been added upon by Q1Group LLC to include further examples, explanations, and links.)
