Even though open enrollment ended Dec 7, 2016, you may be able to change.
Between January 1–February 14, if you’re in a Medicare Advantage Plan, you can leave your plan and switch to Original Medicare. If you switch to Original Medicare during this period, you will have until February 14 to also join a Medicare Prescription Drug Plan to add drug coverage. Your coverage will begin the first day of the month after the plan gets your enrollment form.
Why bother? original Medicare may offer more comprehensive coverage for less cost.
Crown Care Medicare Insurance Navigation 808-254-8088