Mo. Rev. Stat. § 443.922: Scope.

1. Except as provided in subsection 3 of this section, sections 443.920 to 443.925 apply to a mortgage modification.

2. Sections 443.920 to 443.925 do not affect:

(1) Laws governing the required content of a mortgage;

(2) A statute of limitations or other law governing the expiration or termination of a right to enforce an obligation or a mortgage;

(3) A recording statute;

(4) A statute governing the priority of a tax lien or other governmental lien;

(5) A statute of frauds; or

(6) Except as provided in subdivision (8) of subsection 2 of section 443.923, law governing the priority of a future advance.

3. Sections 443.920 to 443.925 do not apply to any of the following modifications:

(1) A release of, or addition to, property encumbered by a mortgage;

(2) A release of, addition of, or other change in an obligor; or

(3) An assignment or other transfer of a mortgage or an obligation.