Missouri Revised Statutes Title XXX. Domestic Relations § 452.830. Appearance at hearing

1. Upon request of the court of another state, the courts of this state which are competent to hear custody matters may order a person in this state to appear at a hearing to obtain evidence or to produce or give evidence under other procedures available in this state for use in a custody proceeding in another state. A certified copy of the transcript of the record of the hearing or the evidence otherwise obtained may, in the discretion of the court and upon payment therefor, be forwarded to the requesting court.

2. A person within this state may voluntarily give his testimony or statement in this state for use in a custody proceeding outside this state.

3. Upon request of the court of another state, a competent court of this state may order a person in this state to appear alone or with the child in a custody proceeding in another state. The court may condition compliance with the request upon assurance by the other state that travel and other necessary expenses will be advanced or reimbursed.