In an interview with EW, director J.J. Abrams revealed that Princess Leia will have a new title in Star Wars Episode VII: The Force Awakens:
“She’s referred to as General. But … there’s a moment in the movie where a character sort of slips and calls her ‘Princess.’”
Well, that character can really only be either Han or C3-PO, in all likelihood. Leia’s mother, Queen Amidala, also left her royal title for another role, that of Senator. Of course Padme doesn’t seem to do a lot of senatoring in the prequels, unless sitting and talking with Anakin counts (seriously, go back and watch them- there’s a lot of just sitting and talking in those films).