As far I understood RMAN features you can't change the backupset location after the backup.
Providing that you have to recover, you will have to put RMAN backupset in the same directory structure.
In case of a disaster recovery, if the new server doesn't have the same structure, you will have to :
1/ recreate a structure of the backupset.
2/
a- If you can recreate the same structure for database
b- If you can't do that, you will have first to restore the controlfile. Make the appropriate changes, then restore and recover your database.

Latyr