California Code, Education Code - EDC § 22138

“Final vesting” means the right of a member or a beneficiary to receive a monthly retirement allowance, disability allowance, a family benefit, or survivor benefits when the member has completed the minimum number of years of credited service, has attained the minimum specified age, has formally terminated his or her active service, has made application for retirement, or has been formally retired in accordance with Section 24201, after which the kind and amount of the retirement allowance is fixed and cannot thereafter be changed except as provided in this part.