Mo. Rev. Stat. § 199.270
Any time after commitment, the patient or, if incapacitated, the patient's legal guardian, or if a minor, a parent or next of kin having reason to believe that such patient no longer has contagious tuberculosis or that his or her discharge will not endanger public health, may institute proceedings by petition, in the circuit court of the county that originally issued the order for commitment, whereupon the court shall set the matter down for a hearing before the court within fifteen days requiring the local public health authority to show cause on a day certain why the patient should not be released. The court shall also require that the patient be allowed the right to be examined prior to the hearing by a licensed physician of the patient's own choice, if so desired, and at the patient's own personal expense. Thereafter all proceedings shall be conducted the same as on the proceedings for commitment with the right of appeal by either party as herein provided; provided, however, such petition for discharge shall not be brought or renewed more than once every six months.
§ 199.270, RSMo