Cal. Gov. Code § 53350

For purposes of financing of, or contributing to the financing of, specified public facilities, the legislative body may by resolution designate a portion or portions of the district as one or more improvement areas. An area shall be known as “Improvement Area No. ____” of “Community Facilities District ____.” After the designation of an improvement area, all proceedings for purposes of a bond election and for the purpose of levying special taxes for payment of the bonds, or for any other change pursuant to Article 3 (commencing with Section 53330), shall apply only to the improvement area for those specified facilities.