How do I change the freuency on my Hampton Bay Fan remote?

I can help you with that but what makes you think its needed? Both the hand held and the receiver in the canopy have a series of very small switches that are eother On or OFF. Both units must match exactly, I usually recommend that you move all the switches to the same location such as all ON or all OFF.

Ballenger is correct. See:

Ceiling fan remote controls - help and FAQ- Ceiling Fans N More