Okla. Admin. Code § 590:15-3-6
In order for the election for transfer to be effective, an Eligible Member must be living at the time the Board receives official written notice from the Internal Revenue Service that this distribution satisfies the tax qualification requirements for governmental plans applicable to such transfers as specified in the Internal Revenue Code. If an Eligible Member dies after the Board receives such official written notice, but before the actual transfer, the Excess Contributions shall be transferred to the Incentive Plan in the same manner as if the Eligible Member were not deceased. Once transferred to the Incentive Plan, distribution shall be governed by the Incentive Plan provisions as provided in 590:35-13-5 and 590:35-13-6. If an Eligible Member dies prior to the Board receiving such official written notice, the Eligible Member's election shall be deemed invalid and shall not be accepted by the System.
Okla. Admin. Code § 590:15-3-6