Missouri Revised Statutes Title XXX. Domestic Relations § 452.747. Verified petition--service of process

1. Any petition for modification of child custody decrees filed under the provisions of section 452.410 or sections 452.700 to 452.930 shall be verified and, if the original proceeding originated in the state of Missouri, shall be filed in that original case, but service shall be obtained and responsive pleadings may be filed as in any original proceeding.

2. Before making a decree under section 452.410 or sections 452.700 to 452.930, the litigants, any parent whose parental rights have not been previously terminated, and any person who has physical custody of the child shall be served in the manner provided by the rules of civil procedure and applicable court rules and may within thirty days after the date of service (forty-five days if service by publication) file a verified answer. If any such persons are outside this state, notice and opportunity to be heard shall be given under section 452.740.