Legal Question in Immigration Law in California

I do not know if you mean that the petition was revoked or denied. In any case, a denial can be appealed. In regard to a revocation (which means the petition was at first approved), USCIS would send you (or rather your employer, the petitioner) a notice of intent to revoke with an opportunity to answer why the petition should not be revoked. You and or your employer should consult with an Immigration Attorney to see what options are available and the best way to appeal the decision.