Mo. Const. art. IV, § 27

1. The governor may control the rate at which any appropriation is expended during the period of the appropriation by allotment and may reduce the expenditures of the state or any of its agencies below their appropriations whenever the actual revenues are less than the revenue estimates upon which the appropriations were based. The governor shall not reduce any appropriation for the payment of principal and interest on the public debt.

2. The governor shall notify the general assembly by proclamation whenever the rate at which any appropriation shall be expended is not equal quarterly allotments, the sum of which shall be equal to the amount of the appropriation. Any rate of expenditure for any appropriation which is not equal quarterly allotments shall stand reconsidered in the chamber in which the bill that contained the appropriation originated. Such reconsideration shall be in the manner that a bill is reconsidered under article III, section 32. Either the general assembly that receives the proclamation or the next general assembly may reconsider the rate of expenditure. If the general assembly successfully reconsiders the rate of expenditure for the appropriation in question, the rate shall be assumed to be equal quarterly allotments. Such reconsideration may be at any time the general assembly is in session including sessions pursuant to article III, sections 20, 20(b), and 32 and article IV, section 9. Either the general assembly that receives the proclamation or the next general assembly may reconsider such allotment allocation change. Such reconsideration may be at any time the general assembly is in session including sessions pursuant to article III, sections 20, 20(b), and 32 and article IV, section 9.

3. The governor shall notify the general assembly by proclamation when the governor reduces one or more items or portions of items of appropriation of money as a result of actual revenues being less than the revenue estimates upon which the appropriations were based. Each item or portions of items of appropriation of money shall stand reconsidered in the chamber in which the bill that contained the appropriation originated. Such reconsideration shall be in the manner that a bill is reconsidered under article III, section 32. Either the general assembly that receives the proclamation or the next general assembly may reconsider such reduction. Such reconsideration may be at any time the general assembly is in session including sessions pursuant to article III, sections 20, 20(b), and 32 and article IV, section 9.