California Code, Government Code - GOV § 19996.1

(a) Resignations from the state civil service are subject to department rules.  A resignation, except as provided in this section, does not jeopardize any rights and privileges of the employee except those pertaining to the position from which he or she resigns.  A written resignation may expressly waive all or any rights or privileges provided for by this chapter, including but not limited to, accumulated vacation, and in such event the records of the department shall be made to conform therewith.  No resignation shall be set aside on the ground that it was given or obtained pursuant to or by reason of mistake, fraud, duress, undue influence or that for any other reason it was not the free, voluntary and binding act of the person resigning, unless a petition to set it aside is filed with the department within 30 days after the last date upon which services to the state are rendered or the date the resignation is tendered to the appointing power, whichever is later.  In the event a resignation is set aside pursuant to this section, the person resigning shall be reinstated to his or her former position and paid his or her salary for the period he or she was removed from state service as the result of such resignation.  From any such salary due there shall be deducted compensation that the employee earned, or might reasonably have earned, during any period commencing more than six months after the initial date of resignation.

(b) If the provisions of this section are in conflict with the provisions of a memorandum of understanding reached pursuant to Section 3517.5, the memorandum of understanding shall be controlling without further legislative action, except that if such provisions of a memorandum of understanding require the expenditure of funds, the provisions shall not become effective unless approved by the Legislature in the annual Budget Act.