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).