Assign a device that was serviced or replaced in Apple Business Manager
Service a device
You need to unassign any devices from their device management service in Apple Business Manager before they’re subject to AppleCare service.
When the device returns from servicing, you can reassign it to the same device management service.
Replace a device
If you replace an iPhone, iPad, Mac, or Apple Vision Pro currently enrolled in Apple Business Manager through an Apple Authorized Service Provider, the replacement device is usually also available for enrollment. You can manually assign the device to a device management service using your order number. To find replacement devices, search for order numbers that begin with the letter R.