70 ILCS 605/9-9

The merger of 2 or more districts into a consolidated district shall not affect the organization or operation of any subdistrict or minor subdistrict within any of the merged districts in existence at the time of consolidation, except to avoid confusion the court may rename or renumber the subdistricts and minor subdistricts. The commissioners and other officers of the consolidated district, ex officio, shall become the commissioners and officers of all subdistricts and minor subdistricts within the consolidated district.