The retirement board is hereby authorized to offer plans, optional with the beneficiary, for the payment of allowances due such beneficiary for retirement, withdrawal or prior service pensions under the retirement system. No plans shall be offered, however, which are not approved by competent actuaries.

When a beneficiary and his or her spouse have been approved for a retirement plan which provides for them a joint life annuity, and their marriage is subsequently dissolved, the board shall permit such beneficiary to convert to the maximum life annuity plan approved by the board: Provided, That the beneficiary shall furnish to the board proof of entry of a final decree of divorce or annulment: Provided, however, That a beneficiary who qualifies for the change of retirement plans afforded by this section shall be permitted only one such change: Provided further, That the recalculated monthly benefits, independently of increases granted by law after the beneficiary's retirement, shall not exceed the monthly benefits which would have been applicable under the maximum life annuity plan at the time the beneficiary retired; and with such recalculation to be effective on the first day of the month following submission to the board by the beneficiary of proof of entry of a final decree of divorce or annulment.

Upon remarriage, a retirant may name the new spouse as an annuitant for any of the survivorship retirement benefit options offered by the provisions of this section: Provided, That the beneficiary shall furnish to the retirement board satisfactory proof of the marriage: Provided, however, That the retirant certifies under penalty of perjury that no qualified domestic relations order that would restrict such a designation is in effect: Provided further, That no cause or action against the board may then arise or be maintained on the basis of having permitted the retirant to name a new spouse as annuitant for any of the survivorship retirement benefit options. The value of the new survivorship annuity shall be the actuarial equivalent of the retirant's benefit prospectively in effect at the time the new annuity is elected.