Cal. RTC § 4831.5

When it can be ascertained by the assessor from an audit of an assessee’s books of account or other papers that there has been a defect of description or clerical error of the assessee in his property statement or in other information or records furnished to the assessor which caused the assessor to assess taxable tangible property which should not have been assessed or to assess it at a substantially higher valuation than he would have entered on the roll if the information had been correctly furnished to the assessor, the error on the roll may be corrected under this article at any time after the roll is delivered to the auditor by the clerk of the county board and within the time allowed for assessing property which has escaped assessment as provided in Sections 532 and 532. 1. The extent and character of the change to be made on the roll shall be certified to the auditor by the assessor.