To decommission or reset your access controller to factory settings, you'll need to decommission it from Command. This will also delete all user-related data from the controller and allow it to be transferred to a new organization.
Select the Devices page from the All Products menu
Select the controller you want to decommission from the list of devices
Select the arrow in the right-hand column to move to the device's page
Select the Settings tab
Select Confirm - this cannot be undone
The controller will now reset. Wait 5 minutes before adding the controller to an organization.