Belt replacement(not timing) on 2004 Honda Odyssey

I have 2 belts on my 2004 Odyssey, 1 is the serpentine, what does the other do? looks like it is runs the A/C compressor. If so, how do i replace it?

Asked by for the 2004 Honda Odyssey
So was it the A/C belt, and were you able to replace it?