Do you mean that is does not rewind tape right off the reel and leaves a couple of turns on the reel?
If so, that will be because of the auto stop which is designed to prevent this - so save you having to rethread the tape.
You have an auto stop set switch on most of their reel to reel machines, and you just switch if to off.
Unless it is one that has a tape reel counter and the auto stop is linked to that, in which case you need to reset the trip on it. Someone else who know more about this particular machine can shed some light on it.