Can I go back to Original Medicare if I try Medicare Advantage?

Yes — anytime during the right window.

• AEP (Oct 15 – Dec 7): Drop MA, return to Original Medicare. Effective Jan 1.
• MA OEP (Jan 1 – Mar 31): Drop MA, return to Original Medicare. Effective the next month.
• SEPs: Available for qualifying life events (moving, losing eligibility, etc.).

TFL is unaffected by the switch. It will simply resume wrapping Original Medicare instead of your old MA plan.

One important note for non-TFL beneficiaries (doesn't apply to you): switching from MA back to Original Medicare can mean losing guaranteed-issue rights for Medigap. For TFL beneficiaries this is irrelevant — you don't need Medigap. Your wraparound is built in.