Mo. Rev. Stat. § 473.030
At any time after the issuance of letters, any person interested in the estate, in person or by attorney, may serve upon the executor or administrator, or upon his attorney, and file with the clerk of the court where the proceedings are pending, with a written acknowledgment of or proof of service, a written request, stating that he desires written notice by ordinary mail of the time and place of all hearings on the settlement of accounts, on final distribution, and on any other matters for which any notice is required by law, by rule of court or by an order in the particular case. The applicant for notice shall include in his written request his post-office address or that of his attorney. Unless the court otherwise directs, upon filing the request the clerk shall give the applicant notice of all hearings for which any notice is required as aforesaid, or of such of those hearings as he designates in his request.
§ 473.030, RSMo