Section 5-16-12 - Addition or withdrawal of territory by a districtA. After the creation of a district, a governmental unit adjacent to but not part of that district may join the district and determine the territorial area to become a part of that district. A two-thirds' affirmative vote by the board shall be required before the governmental unit may join the district. B. A governmental unit that is a member of a district may withdraw from the district by adopting a resolution to withdraw. The governmental unit shall withdraw its representative from the board. Real property owned by the district within the boundaries of the withdrawing governmental unit shall remain the property of the district. The provisions of withdrawal shall be negotiated and agreed to by the board, the governmental unit and the authority.