§ 18. Change in contracts. Any change, addition or deduction made in
any contract by reduction in price, by addition in price or otherwise
must be done by an order on contract which may be issued by the
commissioner of general services. This order shall specifically set
forth conditions of the change or other modification and shall be
approved by the board, department, commission or officer having
jurisdiction. After having been approved by him the order shall be
forthwith filed in the office of the state comptroller.