Cal. Health & Saf. Code § 6550.6
If the district board proposes to change the boundaries of the proposed improvement district by adding territory thereto, the project, the estimate of cost, or the method by which the project is to be financed or to increase the proposed maximum amount of the tax, it shall state the proposed change and the time and place for a hearing thereon in a resolution and give notice of such hearing in the manner required by Section 6550.3. At the time and place fixed for the hearing, or at any time and place to which the hearing is adjourned, the district board shall continue with the hearing. At the hearing any person interested, including any person owning property within the district or within the proposed improvement district, may appear and present any matters material to the changes stated in the notice.
Ca. Health and Saf. Code § 6550.6