BIA Practice Manual ch. 3.9

Whenever a party discovers new authority subsequent to the filing of a Notice of Appeal (Form EOIR-26) or brief, whether that authority supports or detracts from the party’s arguments, that party should notify the Board of the new authority.  See Chapter 3.6(g)(1) (New authorities).  If either party wishes to brief new authority, that party should consult Chapter 3.6(g)(2) (New argument).