Can I change a four wire exhaust fan with a three wire exhaust fan both same size?

Can you change a four wire exhaust fan with a three wire fan on a rheem a/c

What fan are you asking about. Draft inducer, or blower motor? If you can give a little more info we will try to help. Pictures always help.

And, are you talking about the outdoor unit(ac) or indoor furnace unit.

If you are talking about the outdoor fan motor, yes you can but you need a new capasitor.