Mo. Rev. Stat. § 66.411

No county with a charter form of government and with more than two hundred fifty thousand but fewer than three hundred fifty thousand inhabitants shall dissolve, eliminate, merge, or terminate a municipal fire department of any home rule city with more than sixty thousand three hundred but fewer than sixty thousand four hundred inhabitants, until it has been submitted to an election of the voters residing within the home rule city with more than sixty thousand three hundred but fewer than sixty thousand four hundred inhabitants, and assented to by a majority vote of the voters of the city voting on the question.