interior corner wallboard repair
If not, if the tape is just tape and not inside corner-bead, then you probably will not be able to remove it without tearing into the wall. If it is inside-corner-bead, then you can get a piece of the metal and rip it out and re-do it.
If you just have drywall tape, I would sand the corner down below the paint (better adhesion), re-tape it with fiberglass mesh tape (stronger), then smooth a coat of drywall mud (joint compound) over that. You might get a bulky corner, but it is a closet and will be a sound repair.