Mo. Rev. Stat. § 137.270
The county commission of each county may hear and determine allegations of erroneous assessment, or mistakes or defects in descriptions of lands, at any term of the commission before the taxes are paid, on application of any person who, by affidavit, shows good cause for not having attended the county board of equalization for the purpose of correcting the errors or defects or mistakes. If any lot of land or any portion thereof has been erroneously assessed twice for the same year, the county commission shall release the owner or claimant thereof upon the payment of the proper taxes. Valuations placed on property by the assessor or the board of equalization shall not be deemed to be erroneous assessments under this section.
§ 137.270, RSMo
RSMo 1939 § 10998, A.L. 1945 p. 1782 § 24, A.L. 1959 H.B. 108