A power of attorney is a legal device that authorizes one person to perform legal acts -- such as signing a consent to medical treatment -- on behalf of another person. The person who grants the authority is known as the principal, and the person who exercises it is known as the agent or attorney-in-fact. California's power of attorney laws are located in sections 4000 through 4545 of the California Probate Code.
To execute a power of attorney, you must have the legal ability to enter a contract, meaning that you must be mentally competent and at least 18 years old. You must put your power of attorney in writing, sign it, date it and have it witnessed. It can be witnessed by either a notary public or two adults. Witnesses must sign the document. Your agent cannot be a witness and does not have to sign the document.
Modification and Revocation
If your power of attorney contains instructions about how it may be modified or revoked, it may be modified or revoked in accordance with those instructions. Otherwise, you may modify it by creating a new power of attorney. Your power of attorney is automatically revoked if you die, if your agent dies or becomes disabled, or when the purpose of the power of attorney has been fulfilled. Otherwise, you may revoke it by notifying your agent orally or in writing. If you lose mental capacity or become disabled, a court may revoke your power of attorney on your behalf.
A power of attorney may be general or specific. A general power of attorney grants your agent the power to perform any legal act that you are entitled to perform. A specific power of attorney grants your agent the power to perform a specific task, such as selling your home, or to perform a specific legal act, such as signing a title deed. A durable power of attorney continues to be valid even if you become mentally incompetent or unable to communicate, while a non-durable power of attorney automatically expires under these conditions. The power of attorney should clearly specify which powers are granted and whether or not it is durable.
If you amend or revoke a power of attorney, no third party's rights will be affected until he knows or should know of the revocation. If your agent presents the original power of attorney document to a third party, and the third party purchases your home without realizing that your agent's authority has already been revoked, your agent's signature on the purchase contract will bind you to the transaction. You may sue your agent, but you may not reverse the transaction.