If you have a replacement iPhone, iPad, or iPod touch
If Apple or an Apple Authorized Service Provider replaces an iPhone, iPad, or iPod touch enrolled in DEP, the replacement will usually appear in DEP within four hours. It will automatically be assigned to the same server as your original device.
If you have a serviced Mac
If your Mac is enrolled in DEP, and you get it serviced, your Mac remains enrolled unless the logic board is replaced. If the logic board is replaced on your Mac, you can manually re-enroll it in mobile device management.