29 CFR 4221.7 - Reopening of proceedings.
(a) Grounds for reopening. At any time before a final award is rendered, the proceedings may be reopened, on the motion of the arbitrator or at the request of any party, for the purpose of taking further evidence or rehearing or rearguing any matter, if the arbitrator determines that -
(1) The reopening is likely to result in new information that will have a material effect on the outcome of the arbitration;
(2) Good cause exists for the failure of the party that requested reopening to present such information at the hearing; and
(3) The delay caused by the reopening will not be unfairly injurious to any party.
(b) Comments on and notice of reopening. The arbitrator shall allow all affected parties the opportunity to comment on any motion or request to reopen the proceedings. If he or she determines that the proceedings should be reopened, he or she shall give all parties written notice of the reasons for reopening and of the schedule of the reopened proceedings.