Power of attorney does not stay valid after the death of the principal. This document dies with the death of the person, rendering it ineffective. When you are named an individual’s power of attorney you have all the permission to act on their behalf as long as the person is still alive. You gain all the legal authority to manage the affairs and assets of the principal once you sign power of attorney. However, it becomes null and void once the person passes away. Therefore, you lose the authority of managing the principal’s affairs once the principal dies unless you were named as the executor in the estate planning document.