When you initialise Beacon Region then you need to identify at least UUID and it is either hardcoded with in the app or can be placed on the server and should be retrieved from server before calling initialising Beacon Region.
NOTE:You should have a copy of all beacons UUIDs,majors and minors for future purposes
But suppose your Beacon goes out of order then there's a backup plan.
Follow below said steps:
1.Install Estimote-iOS or android app
2.Place the new beacon near to your device and start ranging beacons in estimote app.
3.Then you need to login with your cloud account in your app and configure new beacon(i.e edit your beacon's UUID.)You can even edit major,minor etc
4.Save those settings and your new beacon is configured and ready to use.
Happy Coding :)