Halachicly speaking, if an error is found in a Psak Din or if new information comes to light, the decision can be revoked (see Shulchan Aruch, Choshen Mishpat 25:1-3) by the initial Beis Din or by one of greater authority.

Although the Gemora (Bava Basra 138b) advises that one Beis Din need not check up after another, at a time that Batei Din are less qualified, there is a Halachic basis for a more qualified Beis Din to review their decision (see Pischei Teshuvah Choshen Mishpat 19:3). In the absence of a Beis Din hierarchy, however, this is hardly an easy route to take. This is especially true if the arbitration agreement includes a clause that precludes the option of an appeal, leaving a dissatisfied party without recourse.

Moreover, after the tribunal issues its ruling, it becomes functus officio, which means that the tribunal’s authority is exhausted, and it lacks any power to re-examine its decision, unless the parties sign a new arbitration agreement (see below "Party Consent"). 

The parties can get around this by requesting an "Indicative Ruling." This would provide the parties with an idea of how the panel is likely to rule. It can also assist the parties in resolving their disagreement, save time and money, and provide clarity on the issues in dispute. Due to the non-binding character of an Indicative Ruling, a disgruntled party would be permitted to appeal to the arbitral tribunal within an agreed-upon period and request that it reconsider its pending, final and official decision.

Party Consent 

Because arbitration is a matter of contract, the parties can agree to empower the arbitrators to reconsider an award. While technically not an “exception,” where the parties so agree, the functus officio doctrine is displaced, and the parties’ agreement defines the arbitrators’ authority to reconsider or modify their awards. Parties may grant arbitrators this power in the parties’ arbitration agreement or in an after-the-fact submission of a matter for reconsideration.