California Code, Government Code - GOV § 31831

Any member, whether over or under the minimum age of service retirement, who leaves county service and within 90 days or six months if Section 31840.4 applies thereafter becomes a member of the Public Employees' Retirement System, a retirement system established under this chapter in another county, a member of the State Teachers' Retirement System, or a member of a retirement system of any other public agency of the state that has established reciprocity with the Public Employees' Retirement System subject to the conditions of Section 31840.2, regardless of the amount of county service, may elect deferred retirement pursuant to Article 9 of this chapter, except that he or she may not, after that election, rescind the election or withdraw any of his or her accumulated contributions while a member of such other system.