How to unbind a buttons

I set up pace notes recording/playback some time ago, but but no longer need to use them. I assigned pace notes record/playback to 2 buttons on my button box but I can't find a way to un-bind those 2 buttons. I really need them for other purposes.

Under Command macro editor, I can see my controllers, but not clear if this is the right place and what to do next.

Could someone point me in the right direction on how to unbind buttons, or disable pace note functionality?

Thanks a lot