Mo. Rev. Stat. § 78.030
Upon petition of voters equal in number to twenty-five percent of the votes cast for all candidates for mayor at the last preceding city election of any such city, the mayor shall, by proclamation, submit the question of organizing as a city under sections 78.010 to 78.420 at an election. If said plan is not adopted at the last election, the question of adopting said plan shall not be resubmitted to the voters of said city for adoption within two years thereafter, and then the question to adopt shall be resubmitted upon the presentation of a petition signed by voters as herein provided, equal in number to twenty-five percent of all votes cast for all candidates for mayor at the last preceding election. At such election the proposition to be submitted shall be: Shall the proposition to organize the city of (name of city) under sections 78.010 to 78.420 be adopted? If the majority of the votes cast shall be in favor thereof, cities shall proceed to the election of mayor and councilmen. Immediately after such proposition is adopted, the mayor shall transmit to the governor, the secretary of state and to the county clerk each a certificate stating that such proposition was adopted. At the next municipal election after the adoption of such proposition there shall be elected a mayor and councilmen. In the event, however, that the next municipal election does not occur within six months after such election, the mayor shall, within ten days after such election, by proclamation, call a special election for the election of a mayor and councilmen, sixty days' notice thereof being given in such call.
§ 78.030, RSMo