A Power of Attorney is a document. The document authorizes one person to act for another person. In other words, the person who signs the power of attorney is making another person his agent, or her agent, to do things for him or her. If someone signs a Power of Attorney, he still has authority to do everything that he could already do. He’s not giving up his right to act for himself. Someone who signs a Power of Attorney can revoke that Power of Attorney.