California Code, Government Code - GOV § 31701

Any member may elect to rescind in writing his election and withdraw his accumulated contributions pursuant to Section 31628 at any time before the effective date of his retirement except that if within 90 days after discontinuing service under this system, he became a member of the State Employees' Retirement System or a system established in another county under this chapter, he may not rescind or withdraw any of his accumulated contributions while in service as such a member.