Okla. Stat. tit. 82 § 1324.15
At the time and place set for the hearing and consideration of the petition, the board of county commissioners shall ascertain whether proper notice has been given and whether the statements contained in the petition are true. If true, and if a majority of the members of the Board of the district to which annexation is desired do not object to such statement, the board of county commissioners shall enter into its minutes such findings and shall set forth in said minutes a description of the new boundaries of such district. Thereafter, owners of land located within the annexed territory shall be entitled to subscribe to such benefit units upon such terms and conditions as the board in its discretion may provide. Any owner of land located within any territory annexed to a district who shall subscribe to one or more benefit units and comply with terms and conditions provided by the board, shall be entitled to the same rights as participating members.
Okla. Stat. tit. 82, § 1324.15