California Code, Streets and Highways Code - SHC § 6492.5

(a) The clerk of the legislative body shall send a notice, by certified or registered mail, to the registered holder of any outstanding bond secured by the assessment to be apportioned, stating that an apportionment of an assessment has been requested, and indicating the numbers and amounts of the proposed apportionment. The notice shall also state that, unless a request for a hearing is received within 45 days from the date of mailing of the notice, the apportioned assessments shall become final and be recorded in the office of the street superintendent.

(b) If a request for a hearing under subdivision (a) is received, the legislative body shall file a report and conduct a hearing pursuant to Part 10 (commencing with Section 8730) of Division 10.