The city council, either in a single proceeding or by separate proceedings, may order one or any combination of the following changes of organization:
A. The annexation of territory to an existing assessment district formed under this chapter;
B. The detachment of territory from an existing assessment district formed under this chapter;
C. The dissolution of an existing assessment district formed under this chapter;
D. The consolidation into a single assessment district formed under this chapter of any combination of two or more of any of the following:
1. An existing assessment district formed pursuant to this chapter.
2. Any other district with the same or similar function formed pursuant to the laws of the state or any procedural ordinance of the city. (Prior code § 85.07.700)