16 Pa. Stat. § 11665
At the time of his superannuation retirement, any retiree may elect to receive either his retirement allowance payable throughout life, or to receive the full amount of the accumulated deductions standing to his individual credit in the members' annuity reserve account at the time of his voluntary or involuntary retirement, or he may in any event elect to receive the actuarial equivalent of his member's and county annuity in a lesser retirement allowance payable throughout life with provisions that:
Should a retiree, who has not elected to receive in one payment the full amount of the accumulated deductions standing to his individual credit in the members' annuity reserve account at the time of his retirement pursuant to section 15.1, select a retirement allowance payable throughout his life and fail to receive payments at least equal to his accumulated deductions as of the date of retirement, an amount equal to the balance of his accumulated deductions shall be paid to his legal representative or to a person having an insurable interest in his life, as he shall nominate by written designation filed with the board.
16 P.S. § 11665