38 CFR § 3.104 - Binding nature of decisions.
(a) Binding decisions. A decision of a VA rating agency is binding on all VA field offices as to conclusions based on the evidence on file at the time VA issues written notification in accordance with 38 U.S.C. 5104. A binding agency decision is not subject to revision except by the Board of Veterans' Appeals, by Federal court order, or as provided in §§ 3.105, 3.2500, and 3.2600.
(b) Binding administrative determinations. Current determinations of line of duty, character of discharge, relationship, dependency, domestic relations questions, homicide, and findings of fact of death or presumptions of death made in accordance with existing instructions, and by application of the same criteria and based on the same facts, by either an Adjudication activity or an Insurance activity are binding one upon the other in the absence of clear and unmistakable error.
(c) Favorable findings. Any finding favorable to the claimant made by either a VA adjudicator, as described in § 3.103(f)(4), or by the Board of Veterans' Appeals, as described in § 20.801(a) of this chapter, is binding on all subsequent agency of original jurisdiction and Board of Veterans' Appeals adjudicators, unless rebutted by evidence that identifies a clear and unmistakable error in the favorable finding. For purposes of this section, a finding means a conclusion either on a question of fact or on an application of law to facts made by an adjudicator concerning the issue(s) under review.