Cal. Gov. Code § 21193
If the determination pursuant to Section 21192 is that the recipient is not so incapacitated for duty in the position held when retired for disability or in a position in the same classification or in the position with regard to which he or she has applied for reinstatement and his or her employer offers to reinstate that employee, his or her disability retirement allowance shall be canceled immediately, and he or she shall become a member of this system.
If the recipient was an employee of the state or of the university and is so determined to be not incapacitated for duty in the position held when retired for disability or in a position in the same class, he or she shall be reinstated, at his or her option, to that position. However, in that case, acceptance of any other position shall immediately terminate any right to reinstatement. A recipient who is found to continue to be incapacitated for duty in his or her former position and class, but not incapacitated for duty in another position for which he or she has applied for reinstatement and who accepts employment in the other position, shall upon subsequent discontinuance of incapacity for service in his or her former position or a position in the same class, as determined by the board under Section 21192, be reinstated at his or her option to that position.
If the recipient was an employee of a contracting agency other than a local safety member, with the exception of a school safety member, the board shall notify it that his or her disability has terminated and that he or she is eligible for reinstatement to duty. The fact that he or she was retired for disability does not prejudice any right to reinstatement to duty which he or she may claim.
Ca. Gov. Code § 21193