Mo. Rev. Stat. § 448.150
Unless a greater percentage is provided for in the declaration or bylaws, and notwithstanding the provisions of sections 448.130 and 448.140, a majority of the unit owners where the property contains two units, or not less than sixty-six and two-thirds percent where the property contains three units, and not less than seventy-five percent where the property contains four or more units may, by affirmative vote at a meeting of unit owners duly called for such purpose, elect to sell the property. Such action shall be binding upon all unit owners, and it shall thereupon become the duty of every unit owner to execute and deliver such instruments and to perform all acts as in manner and form may be necessary to effect the sale. Any unit owner who did not vote in favor of such action and who has filed written objection thereto with the manager or board of managers within twenty days after the date of the meeting at which such sale was approved shall be entitled to receive from the proceeds of such sale an amount equivalent to the value of his interest, less the amount of any unpaid assessments or charges due and owing from such unit owner. The "value of such interest", for the purposes of sections 448.005 to 448.210, shall be that percentage of the total value of the property determined by fair appraisal which represents the ownership percentage of the common elements allocated to the unit owned by such objecting owner.
§ 448.150, RSMo