Mo. Rev. Stat. § 546.030
No person indicted for a felony can be tried unless he be personally present, during the trial; nor can any person be tried or be allowed to enter a plea of guilty in any other case unless he be personally present, or the court and prosecuting attorney shall consent to such trial or plea in the absence of the defendant; and every person shall be admitted to make any lawful proof by competent witnesses or other testimony in his defense; provided, that in all cases the verdict of the jury may be received by the court and entered upon the records thereof in the absence of the defendant, when such absence on his part is willful or voluntary, and when so received and entered shall have the same force and effect as if received and entered in the presence of such defendant; and provided further, that when the record in the appellate court shows that the defendant was present at the commencement or any other stage of the trial, it shall be presumed, in the absence of all evidence in the record to the contrary, that he was present during the whole trial.
§ 546.030, RSMo