Cal. Unemployment Insurance Code § 1331

Any base period employer shall, within 15 days after mailing of a notice of computation, submit to the department any facts then known which he or she was not previously required to submit to the department under Section 1327 which may affect the claimant’s eligibility for benefits. The 15-day period may be extended for good cause. If after such 15-day period the employing unit acquires knowledge of facts which may affect the eligibility of the claimant and such facts could not reasonably have been known within the period, the employing unit shall, within 10 days of acquiring such knowledge, submit such facts to the department. The 10-day period may be extended for good cause. The department shall make a determination or reconsidered determination thereon and shall promptly notify the claimant and the base period employer submitting the facts of the determination or reconsidered determination and the reasons therefor. An appeal may be taken in the manner prescribed in Section 1328. The director shall be an interested party to any appeal.