How do I remove a power of attorney that I gave my sister 1 year ago?

You can revoke the power of attorney by executing a revocation of the power of attorney and delivering it to your agent and other third parties that may have relied on it; you may also want to record the revocation. Another way to revoke the current power of attorney is by executing a new power of attorney and include language in the new instrument how it revokes all prior instruments. Section 709.2110 of the Florida Statutes addresses revocations. All the best.