You can't have one TSM server just read the data from a tape written by another TSM server if that tape is a DBB or a storage pool volume. If the tape is a backupset or an export volume then you have some choices.
Assuming this is a storage pool volume and your first TSM server is still around you can configure server to server communications and perform an "export node" command for each node until all of the data from the first TSM server is on the new TSM server. And thus on tapes written by the new TSM server.
If your old TSM server is not around you would need to restore it from its last DBB and then perform the export step above.
If this is an export volume for a single node then you can perform an import node command referencing this volume.
If it is a backupset then you can define the backupset to the new server and that will allow the client to restore files. And that is all you can do with it.
Read up on those commands as some have restrictions.
