During the Medicare Open Enrollment period, from October 15 to December 7, you can make many changes to your Medicare coverage, depending on the coverage you already have. You can change from traditional Medicare to a Medicare Advantage plan (or vice versa). If you prefer Medicare Advantage, you can choose among the Medicare Advantage plans offered in your area during this period. If you are in traditional Medicare, and want prescription drug coverage, you can choose among Medicare prescription drug plans.