Missouri Revised Statutes Title IX. Suffrage and Elections § 115.337. City election authority to assist county election authority, verify signatures, when

1. When an election authority for a county and an election authority for a city have jurisdiction within the same county, the county election authority may, for the purpose of verifying signatures on any new party or independent candidate petition filed with its office, deliver copies of petition pages to the city election authority for registration verification. The city election authority receiving a copy of petition pages shall check each signature indicated by the county election authority against its registration records and return all such copies to the county election authority no later than the day designated by the county election authority. At the same time the copies are returned, the city election authority shall certify to the county election authority the page number of each page it received and the total number of valid signatures from the city on the pages. The county election authority shall not designate any deadline for returning copies and certifications which is less than six or more than twelve working days after the copies have been received by the city election authority.

2. If copies of petition pages are sent to a city election authority for registration verification under the provisions of this section, the county election authority's final determination on the number of valid signatures submitted on the petition from the city shall be based on the certification made by the city election authority.