Cal. Gov. Code § 53339.5
At the hearing, protests against the proposals described in the resolution of intention may be made orally or in writing by any interested person. Any protests pertaining to the regularity or sufficiency of the proceedings shall be in writing and shall clearly set forth the irregularities or defects to which objection is made. All written protests shall be filed with the clerk of the legislative body prior to the time fixed not personally presented by the author thereof at the hearing for the hearing. The legislative body may waive any irregularities in the form or content of any written protest and at the hearing may correct minor defects in the proceedings. Written protests may be withdrawn in writing at any time before the conclusion of the hearing.
Ca. Gov. Code § 53339.5