Snapping IK FK rigs

Slowly but surely i’m gettin hang of the while IK with FK rigs, but one thing I can’t seem to find. I wanted to make my IK and FK able hit button and snap them to where the other is. You know, I move FK parts about and the Identicle parts hit button and suddenly jump to where the FK is placed so I can change which is main influence and reposition from that spot.