Okla. Stat. tit. 82 § 1324.21
In the event that landowners within a district desire to withdraw from such district, fifty-one percent (51%) of the affected landowners or the board of directors by resolution may petition the county commissioners to release those lands from the district. The petition shall describe by section or fraction thereof and by township and range the lands affected. After a finding that the granting of the petition is to the best interests of the affected landowners and the district, the board of county commissioners shall issue a certificate stating that the lands involved are released and separated from the district. Full minutes of the hearing shall be entered in the journal of the board of county commissioners and the certificate shall be delivered to the secretary of the district who shall, within thirty (30) days, cause the records of the district to be amended to exclude the lands affected. Notice shall be given, as provided in Section 1324.5 of this title, of the filing of a petition for release of lands as provided herein, fixing the time and place of hearing, and a copy of said notice shall be sent by certified mail to the chairman of the board of directors of the district in which the said lands are located.
Okla. Stat. tit. 82, § 1324.21