britcon,
If you could reverse the motor, that would obviously make the air flow go the direction you want. Turing the fan blade assembly over won't accomplish what you want.
If the motor is a permanent magnet motor, it should be reversible by swapping leads. The very best scenario would be to find the manufacturer and give them a call...or ID the thing here, and maybe a member of the forum has "been there, done that".
Stuart
