Okla. Stat. tit. 84 § 25
Such disclaimer shall be effective upon being filed in the district court in which the estate of the person by whom the interest was created or from whom it would have been received is, or has been, administered or, if no probate administration has been commenced, then in the district court of any county provided in Oklahoma Statutes as the place for probate administration of the estate of such person. A copy of the disclaimer shall be delivered or mailed to the representative, trustee or other person having legal title to, or possession of, the property in which the interest disclaimed exists, and no such representative, trustee or person shall be liable for any otherwise proper distribution or other disposition made without actual notice of the disclaimer. If an interest in or relating to real estate is disclaimed the original of the disclaimer, or a copy of the disclaimer certified as true and complete by the clerk of the district court wherein the same has been filed, shall be filed in the office of the county clerk in the county or counties where the real estate is situated and shall constitute notice to all persons only from and after the time of such filing.
Okla. Stat. tit. 84, § 25