Mo. Rev. Stat. § 454.1677: Procedure to register child support order of foreign country for modification.

A party or support enforcement agency seeking to modify, or to modify and enforce, a foreign child support order not under the Convention may register that order in this state under sections 454.1632 to 454.1653 if the order has not been registered. A petition for modification may be filed at the same time as a request for registration, or at another time. The petition must specify the grounds for modification.