California Code, Government Code - GOV § 31486.5

A member who retires for service prior to the age of becoming eligible for benefits described under subdivision (f) of Section 31486.1 may, with the approval of the board, elect to have the retirement pension increased prior to the eligible age and reduced after that age by amounts which have equivalent actuarial values.  This modification is for the purpose of coordinating a member's retirement pension with that received from the federal system.