Section 868 Of Article 6. State Assessed Property Escaping Assessment From California Revenue And Taxation Code >> Division 1. >> Part 2. >> Chapter 4. >> Article 6.

. If, before the expiration of the time prescribed in Section 866 for making an escape assessment, the taxpayer has consented in writing to allow an assessment after that time, the assessment may be made by the board at any time prior to the expiration of the period agreed upon. The period may be extended by subsequent agreements in writing made before the expiration of the period previously agreed upon.