In case an existing CM12 client has to be refreshed (new device), the new device will be staged with CM12.
ConfMgr will install a new OS with a custom name, and when the installation process is finished, the new staged client - the device will get a new name, the old one of the refreshed
device - will be joined to the domain. 
The question is: "How to keep the device’s advertisements?"

The answer is the following:
If AD system discovery is enabled
and it runs ahead of the Configuration client’s Discovery Data Collection Cycle, you will see two computer records...  
To avoid this, the thing you need to do is: to temporarily disable AD system discovery or, specify a less frequency than the one configured in heartbeat discovery method.
Once the computer name is updated into the database, it will also be updated in the collection.

For example, the original computer name is ComputerA. It’s added into Collection A. Later the computer name is changed to ComputerB.
When the heartbeat DDR of ComputerB is processed and updated into ConfMgr database, you will find that ComputerA disappears from Collection A. Instead it is changed to ComputerB automatically. 
Therefore the existing advertisements are still applicable to the updated computer.