California Code, Education Code - EDC § 88117

(a) A person laid off because of lack of work or lack of funds shall be eligible for reemployment for a period of 39 months as follows:

(b) An employee who takes a voluntary demotion or a voluntary reduction in assigned time in lieu of layoff or to remain in his or her present position rather than be reclassified or reassigned, shall be granted the same rights as persons laid off and shall retain eligibility to be considered for reemployment for an additional period of up to 24 months, provided that the same tests of fitness under which the employee qualified for appointment to the class still apply. The personnel commission shall make the determination of the specific period of eligibility for reemployment on a class-by-class basis.

(c) An employee who takes a voluntary demotion or a voluntary reduction in assigned time in lieu of layoff shall be, at the option of the employee, returned to a position in his or her former class or to a position with increased assigned time as vacancies become available, and without limitation of time, but if there is a valid reemployment list the employee shall be ranked on that list in accordance with his or her proper seniority.