How do I 'un-assign' hardware?

Let's say I have a customer with an ATA issue and I have to swap out their hardware. I don't see anywhere in the reseller CP that will allow me to remove the current hardware/MAC address so I can re-assign it new equip.

Am I looking right past it somewhere?

Its my understanding that you would contact VoIPo support and give them the new mac address and they will handle it. Not sure though wish we could manage it our self if possible...