Use doable using DataViewer
Quoted:
"If subscriber aliases are not the same between systems, you can use the
Data Viewer to remap the aliases in the backup to aliases on the new
system. The Data Viewer lets you open up any of the DB files created by
the export process and view the data. There is a simple “export to CSV”
functionality that is used to map old Subscriber aliases to new Subscriber
aliases. You should make a copy of your primary backup DB and use the copy
to run the alias mapping because this function permanently rewrites the
contents of the DB that is used."
Here is the reference.
https://www.netcraftsmen.com/notes-on-the-cobras-migration-tools-for-cisco-unity-and-unity-connection/