Answer: defector

AnswerCrossword Clue
DEFECTORDeserter.
DEFECTORForsaker of a party, group, etc.
DEFECTORBaryshnikov, e.g.
defectorto forsake one cause, party, or nation for another often because of a change in ideology
defectorone that defects (to desert an allegiance)
defectorleave one situation (as a job) often to go over to a rival the reporter defected to another network