Okla. Stat. tit. 11 § 13-114
Where a municipality has adopted a charter containing a special provision to the effect that at the expiration of a specified period after the adoption of the charter the governing body may submit to the registered voters of the municipality the question of whether or not the charter shall be abandoned and the municipality governed under a statutory form of government, and the specified time has expired and the governing body has failed to submit the question, then the question shall be submitted to the registered voters at the next election which may be held in the municipality. The secretary of the county election board shall submit the question substantially in the language of the charter provision. If a majority of the votes cast, as certified by the secretary of the county election board, are in favor of abandoning the charter and adopting a statutory form, the results of the election shall be certified to the Governor in the manner provided for revocation of charters.
Okla. Stat. tit. 11, § 13-114