California Code, Business and Professions Code - BPC § 2439

(a) Every licensee is exempt from the payment of the renewal fee and requirement for continuing medical education if the licensee has applied to the Division of Licensing for a retired license. The holder of a retired license may not engage in the practice of medicine or the practice of podiatric medicine.

(b) If a physician and surgeon has applied to convert from retired status to active status on or after January 1, 2004, but prior to January 1, 2005, the fee to change license status shall be waived, unless the change in status coincides with the physician and surgeon's license renewal date. The board shall refund any fees paid by a physician and surgeon to change from retired to active status after January 1, 2004, and before January 1, 2005, unless the change in status coincides with the physician and surgeon's license renewal date.