Okla. Stat. tit. 18 § 381.42
When a deposit account is held in any association or federal association by a person who becomes incompetent and an adjudication of incompetency has been made by a court of competent jurisdiction, such an association may pay or deliver the withdrawal value of such deposit account and any earnings that may have accrued thereon to the guardian or conservator for such person upon proof of the appointment and qualification of such guardian or conservator. However, if such association has received no written notice and is not on actual notice that such deposit account holder has been adjudicated incompetent, it may pay such funds to such holder or transfer the deposit account on the order of the deposit account holder, and such payment or transfer shall be a valid and sufficient release and discharge of the association for the payment or transfer so made.
Okla. Stat. tit. 18, § 381.42