California Code, Civil Code - CIV § 2356

(a) Unless the power of an agent is coupled with an interest in the subject of the agency, it is terminated by any of the following:

(b) Notwithstanding subdivision (a), any bona fide transaction entered into with an agent by any person acting without actual knowledge of the revocation, death, or incapacity shall be binding upon the principal, his or her heirs, devisees, legatees, and other successors in interest.

(c) Nothing in this section shall affect the provisions of Section 1216.

(d) With respect to a proxy given by a person to another person relating to the exercise of voting rights, to the extent the provisions of this section conflict with or contravene any other provisions of the statutes of California pertaining to the proxy, the latter provisions shall prevail.