NPC (Dorn) has a wrong portrait thanks to CHARACTERNAME using his.

Is there a way to use the inteded portrait for an NPC after the npc has joined the party and you have progressed quite a while afterwards, but not wanting to start a new game?

This would be easier if NPC used their own portraits no matter what, player can always change their own in game but for the NPC it's not so simple.

Edit: If it is doable, enabling appearance change (at least portraits) feature for companion NPC would make things easier.

Thanks