Mo. Rev. Stat. § 506.260
In lieu of mailing such notification to the defendant in a foreign state, plaintiff may cause said notification to be personally served in the foreign state on the defendant by an adult person not a party to the suit by delivering said notification to the defendant or by offering to make such delivery in case defendant refuses to accept same, or by having said notification served on defendant by an officer duly qualified to serve legal process in the state or jurisdiction where the defendant is found and the officer's return showing such service to have been made filed in the case on or before the return day of the process, or within such further time as the court may allow. Upon such service a general judgment may be taken against defendant or defendants.
§ 506.260, RSMo