Switching buffers dynamically

Hey, I am trying to switch buffer data dynamically (i.e. during program execution). I tried just using an alBufferData command to link new data to the existing buffer; that didn't work. I then tried deleting the buffer & source using their respective alDelete commands and then building new ones with the new buffer date; that didn't work. So I am at a loss as to how I can actually switch. Do I have to stop playback or some other step? I don't know.

Any help appreciated,
Ben Pazolli