Mo. Rev. Stat. § 64.906
In any county of the first classification without a charter form of government which has a population of at least one hundred fifty thousand inhabitants which contains all or a portion of a city with a population of at least three hundred thousand inhabitants, the county planning and zoning commission may, with the approval of the governing body of the county, create and adopt rules for the transaction of its business, create and adopt rules for the filing of applications, hearings, inspections and other activities and rules and regulations governing the conduct and procedures of its meetings and hearings. Such rules and regulations may include without limitation such provisions regulating rezoning, land use or platting applications, discovery and prehearing procedures, filing requirements for land use and platting applications, rules regulating the conduct of hearings, the filing of briefs and motions, prefiling of exhibits and witness lists or provisions preventing refiling of zoning or land use applications where the application is the same, or substantially the same, as an application which has been previously overruled, rejected or denied within the previous five years, unless the applicant can show by clear and convincing evidence that a substantial change in circumstances has occurred since the previous rejection which is a result of new facts which were not discoverable by the applicant during the previous proceedings with the use of reasonable diligence or is a result of material facts which have arisen since the previous proceedings were terminated. The rule may further provide that such showing shall be made prior to acceptance of the new application.
§ 64.906, RSMo