Cal. Education Code § 22308

(a) Subject to subdivision (d), the board may, in its discretion and upon any terms it deems just, correct the errors or omissions of any member or beneficiary of the Defined Benefit Program, and of any participant or beneficiary of the Cash Balance Benefit Program, if all of the following facts exist: (1) The error or omission was the result of mistake, inadvertence, surprise, or excusable neglect, as each of those terms is used in Section 473 of the Code of Civil Procedure. (2) The correction will not provide the party seeking correction with a status, right, or obligation not otherwise available under this part. (b) Failure by a member, participant or beneficiary to make the inquiry that would be made by a reasonable person in like or similar circumstances does not constitute an “error or omission” correctable under this section. (c) Subject to subdivision (d), the board may correct all actions taken as a result of errors or omissions of the employer or this system. (d) The duty and power of the board to correct errors and omissions, as provided in this section, shall terminate upon the expiration of obligations of the board, system, and plan to the party seeking correction of the error or omission, as those obligations are defined by Section 22008. (e) Corrections of errors or omissions pursuant to this section shall be such that the status, rights, and obligations of all parties described in subdivisions (a), (b), and (c) are adjusted to be the same that they would have been if the act that was taken or would have been taken, but for the error or omission, was taken at the proper time. However, notwithstanding any of the other provisions of this section, corrections made pursuant to this section shall adjust the status, rights, and obligations of all parties described in subdivisions (a), (b), and (c) as of the time that the correction actually takes place if the board finds any of the following: (1) That the correction cannot be performed in a retroactive manner. (2) That even if the correction can be performed in a retroactive manner, the status, rights, and obligations of all of the parties described in subdivisions (a), (b), and (c) cannot be adjusted to be the same as they would have been if the error or omission had not occurred.