I have a damaged offsite tape.  How do I create another one
form the onsite tape...  Any help would greatly be appreciated

If you also have an onsite copy storage pool reflecting that data,
I would proceed with Delete Volume on that tape and let the next
Backup Stgpool recreate the data.  If no onsite copy storage pool,
you would be gambling that the primary storage pool volume(s) would
be perfect.  I would do a Move Data on the failed volume, as the
safest way to proceed, deleting the volume after everything which
can be moved has been.  (You can't do a Restore Volume, of course,
as the tape is not in a primary storage pool.)

   Richard Sims