The board of directors, if it deems it is not for the best interest of the district that a change of its boundaries be so made as to include therein the lands mentioned in the petition, shall order that the petition be rejected. If it deems it is for the best interest of the district that the boundaries of the district be changed and if no person interested in the proposed change of its boundaries shows cause in writing why the proposed change should not be made or if, having shown cause, such person withdraws the same, the board may order that the boundaries of the district be so changed as to include therein the lands mentioned in the petition, or some part thereof. The order shall describe the boundaries of the included lands and it shall clearly show the change in the boundaries of the district.