Mo. Rev. Stat. § 251.430

Within ninety days of the issuance by the governor of an order creating a regional planning commission, any local unit of government within the boundaries of such region may withdraw from the jurisdiction of such commission by a two-thirds vote of the members of the governing body after a public hearing of which notice shall have been given not more than three nor less than two weeks prior thereto by registered mail to the commission and to the public by publication in a newspaper of general circulation within the boundaries of such local unit of government. A local unit may withdraw from a regional planning commission at the end of any fiscal year by a two-thirds vote of the members of the governing body.