Cal. Civ. Proc. Code § 1288.2

A response requesting that an award be vacated or that an award be corrected shall be served and filed not later than 100 days after the date of service of a signed copy of the award upon:

(a) The respondent if he was a party to the arbitration; or

(b) The respondent’s representative if the respondent was not a party to the arbitration.