Configure the new library as a new one and change data path on the storage policy copy, export and import media, de configure the old library:
"First you must change the data path from the CommCell Console.
This operation logically changes the data path For the associated media within the CommServe database.
Next you must physically move the media from the source library to the destination library.
It is strongly recommended that when you move the media, you use the CommCell Console to export the media from the source library and immediately import them in the target library.
In the case of tape library, the new library may read the barcode patterns differently. In such a situation, update the media barcodes to use the media in the library. See Update Media Barcodes for more information.
Important
Change Data Path (right-click option) should not be performed on Storage Policies with Storage Policy Copies that have Alternate Data Paths (GridStor). If Change Data Path is performed on such a setup, data recovery operations can be performed from the media. However, subsequent data protection operations will not re-use the migrated media."
Source:
https://documentation.commvault.com/2022e/expert/10941_change_data_path_overview.html
Not sure though how this will respond to already replicated VTL data.