Cal. Gov. Code § 31627.2

In any county in which the provisions of Section 31676.1 apply, any member who has additional contributions under Section 31504 of the Government Code, or under Section 31627 of the Government Code, may elect in writing to have all or any part of his accumulated additional contributions returned to him. The portion returned shall not be included in the calculation of the member’s annuity. The board may order payment in whole or in part withheld for a period not to exceed 90 days after receipt of such written election.