38 CFR 21.4003 - Revision of decisions.
The revision of a decision on which an action was predicated will be subject to the following sections:
(a) Clear and unmistakable error, § 3.105(a) of this chapter;
(b) Difference of opinion, § 3.105(b) of this chapter;
(c) Character of discharge, § 3.105(c) of this chapter;
(d) Severance of service connection, § 3.105(d) of this chapter;
(e) Veteran no longer totally and permanently disabled, § 21.4135(o).