With respect to a special tax district formed under Section 43.10.17, as an alternate and independent procedure for making the changes described in Section 53330.7 of the Act, the changes may be made with the unanimous approval of the owner or owners of the parcel or parcels that will be affected by the change and the written consent of the local agency. No additional hearings or procedures are required, and the unanimous approval shall be deemed to constitute a unanimous vote in favor of the proposed changes. If the proceeds of a special tax are being utilized to retire any debt incurred pursuant to this chapter and the unanimous approval relates to the reduction of the special tax rate, the unanimous approval shall recite that the reduction or termination of the special tax would not interfere with the timely retirement of that debt.