N647RA is taken. It's currently assigned to a 2012 Air Tractor Inc AT-402B registered in Salt Lake City, UT.
See the full aircraft record →A tail number only frees up if the owner deregisters the aircraft or moves it to a different N-number — and even then the FAA holds it before releasing it to the public.
N647RA has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N647RA that aren't assigned or reserved: