To reset your Access Controller to factory settings, you'll need to decommission it from Command. This will also allow the controller to be transferred to a new organization.
Select Admin in the menu on the left then select Devices in the submenu. Find the controller you want to decommission and click on the ellipsis icon ⋮ to the right of the controller name
To finalize the decommission select Confirm
The controller will now reset. Wait 5 minutes before adding the controller to an organization.