Mo. Rev. Stat. § 257.460
In any case of a proceeding before the court where a notice is provided for in this chapter, if the court finds for any reason that due notice was not given, the court shall not thereby lose jurisdiction, and the proceeding in question shall not be void; but the court shall in that case order due notice to be given, and shall continue the hearing until such time as notice shall be properly given, and thereupon shall proceed as though notice had been properly given in the first instance. In case the original notice as a whole was sufficient, and was faulty only with reference to publication as to certain tracts or areas, only the owners of and persons interested in those particular tracts or areas need be notified by such subsequent notice. If the publication of any notice in any county was defective or not made in time, republication of the defective notice need be had only in the county in which the defect occurred.
§ 257.460, RSMo