Assign a device that was serviced or replaced in Apple Business Manager
Service a device
You should unassign the following devices from the mobile device management (MDM) server in Apple Business Manager before the device is subject to AppleCare service:
iPhone
iPad
Apple TV
Note: Mac computers do not have to be unassigned.
When the device is returned, you can reassign it to the same MDM server.
Replace a device
If you replace an iPhone, iPad or Mac currently enrolled in Apple Business Manager through an Apple Authorised Service Provider, the replacement device is usually also available for enrolment. You can manually assign the device to a server using your order number. To find replacement devices, search for order numbers that begin with the letter R.
If you replace a device that was assigned to a specific MDM server, the replacement device is automatically assigned to the same server.