Cal. Civ. Code § 1526
(b) Notwithstanding subdivision (a), the acceptance of a check or draft constitutes an accord and satisfaction if a check or draft is tendered pursuant to a composition or extension agreement between a debtor and its creditors, and pursuant to that composition or extension agreement, all creditors of the same class are accorded similar treatment, and the creditor receives the check or draft with knowledge of the restriction.
A creditor shall be conclusively presumed to have knowledge of the restriction if a creditor either: