Assign a device that was serviced and replaced in Apple Business Manager
If you replace an iPhone, iPad, or iPod touch 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 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 mobile device management (MDM) server, the replacement device is automatically assigned to the same server.
If you have a Mac enrolled in Apple Business Manager and that Mac is serviced, it remains enrolled unless the logic board is replaced. If your Mac logic board is replaced, you can reenroll the Mac in mobile device management manually.