For cross server restore, the destination server must have an instance defined in Commvault and that instance needs to be the same name as the source instance. This is a requirement of RMAN in order for it to identify the backup information in the catalog. The destination instance does not need to be open, but started in a no mount state. It also has to be registered in Commvault on that client in order for that client to show in the "drop-down" list.
For cross server "duplicate" restore the SID can and typically must be a different name, unless the "duplicate for standby" option is used.
Ernst F. Graeler
Applications and File Systems