Okla. Stat. tit. 58 § 262
It shall be lawful for any person or persons to whom letters testamentary or of administration have been granted, by the proper authority in any of the United States or the territories thereof, to maintain or defend any suit or action, and to prosecute and recover any claim in the courts of the State of Oklahoma, in the same manner as if the letters testamentary or of administration had been granted to such person by the proper authority in this state, and the letters testamentary or of administration, or a copy thereof, certified under the seal of the authority granting the same, shall be sufficient evidence to prove the granting thereof, and that the person therein named has administration; Provided, that the courts in which any action may be brought by any nonresident executor or administrator shall have power, and such power is hereby given to the said court, upon motion, to require from such person the security required by law in a like case from a resident administrator or executor; Provided, further, that such executor or administrator shall have the authority to release mortgages in this state upon filing with the county clerk of the county in which such mortgage is recorded a showing properly certified to that such executor or administrator is the duly qualified and acting executor or administrator of such estate.
Okla. Stat. tit. 58, § 262