Cal. Sts. & High. Code § 36540

In addition to the changes authorized to be made in the annual report filed with the city council pursuant to Section 36533 or at the conclusion of the public hearing on the annual levy of the assessments, the advisory board may, at any time, recommend that the city council modify the boundaries of the area, any benefit zones within the area, the basis and method of levying the assessments, and any improvements or activities to be funded with the revenues derived from the levy of the assessments. Any modification shall be made pursuant to this chapter.