Instructions to the levying officer may be taken only from the attorney of record. The attorney shall have authority to receive money claimed by a client in an action or proceeding during the pendency thereof, or after judgment, unless a revocation of the attorney's authority is filed, and upon the payment thereof, and not otherwise, to discharge the claim or acknowledge satisfaction of the judgment. An attorney in an action or special proceeding may be changed at any time before or after judgment or final determination either upon the consent of both client and attorney filed with the clerk, or entered upon the minutes; or upon the order of the court, upon the application of either client or attorney, after notice from one to the other. The former attorney must be recognized as the exclusive agent for the client until such time as written notice of the change and of the substitution of a new attorney or of the appearance of the party in person is given to the adverse party. (CCP 283, 284, 285)