The Commissioner may grant a new hearing in a cause determined by him or her on the ground of newly discovered evidence when a petition, setting forth the substance of such evidence, verified by the oath of the petitioner, is presented. His or her decision in granting or denying such hearing shall be final and conclusive. If a party petitions the Commissioner for a new hearing, he or she shall give the adverse party notice of such petition by a citation signed by the Commissioner served like a summons at least 12 days before the date of such hearing. A new hearing shall not be granted on a petition unless the citation to the adverse party is served within six months after the date of the order of the Commissioner.