Changes may be made in the rate or additional rate or levy or in the uses to which the revenue shall be put as specified in the ordinance establishing the area, by ordinance adopted after a hearing before the city council.

The city council shall adopt a resolution of intention to change the rate or additional rate or levy or the uses to which the revenue shall be put at least 15 days prior to the hearing required by this section. This resolution shall specify the proposed change and shall give the time and place of the hearing.