Mo. Rev. Stat. § 510.110
If the court shall be of the opinion that the affidavit is insufficient, it shall permit the same to be amended; and if after such amendment the affidavit does not contain a sufficient statement of facts as herein required, the court shall overrule the same; but if, upon the contrary, the court shall find the affidavit sufficient, the cause shall be continued, unless the opposite party will admit that the witness, if present, would swear to the facts set out in said affidavit, in which event the cause shall not be continued, but the party moving therefor shall read as the evidence of such witness the facts so stated in such affidavit and the opposing party may disprove the facts disclosed, or prove any contradictory statements made by such absent witness in relation to the matter in issue and on trial.
§ 510.110, RSMo