Okla. Admin. Code § 715:10-15-11
A designation of beneficiary or joint annuitant must be made when the retirement contract is completed. A member who selects the Maximum, Option 1 or Option 4 retirement plan may name more than one beneficiary. Once the member has been retired for more than sixty (60) days or if no change in the member's retirement plan occurs, beneficiaries named for the Maximum, Option 1, or Option 4 retirement plan may be changed by the member at any time in the manner prescribed by TRS. The joint annuitant for the Option 2 or Option 3 retirement plan cannot be changed even if the joint annuitant dies before the member, providing, however, the retired member may designate a beneficiary different from the joint annuitant to receive the $5,000 death benefit. The member who elects the Option 4 retirement plan must name a beneficiary, who can be any living person or persons, or a trust. The beneficiary does not have to be a spouse or dependent. In the case of a divorce the retirement contract remains in force and the member's joint annuitant (ex-spouse) will receive the member's monthly benefit after the member's death (if named as a joint annuitant) unless a Court, acting through a Qualified Domestic Relations Order, directs otherwise. A beneficiary designation is valid for TRS purposes when properly executed and on file with TRS prior to the death of the member. TRS shall not be responsible for determining the competency of a member to designate a beneficiary except as otherwise provided by Oklahoma law.
Okla. Admin. Code § 715:10-15-11