You'd have to do a RESTORE and RECOVER database as if you were doing Disaster Recovery to another server.
See "Restoring the Database to a New Host" at http://docs.oracle.com/cd/B10501_01/server.920/a96566/rcmrecov.htm#1007514
Hemant K Chitale
Thanks Hemant for the reply.
I too have gone through the above doc before posting my query here. Yes i can follow above post to implement the clone but the challenges i face here are:
I can't use/specify the same backup location for both PROD and STAGE while performing the clone(creating DUPLICATE database).
The RMAN backup on source(PROD) is copied to some other mount and that mount is now mounted on to the STAGE server. So, If i have to use this backup to clone the stage instance i have to catalog(with CATALOG BACKUPPIECE) it at the destination(STAGE) side. but as the backup is in the form of BACKUPPIECE it's not possible to catalog a BACKUPPIECE in Oracle Release 9i, whereas you can catalog datafiles, archivelogs, controlfiles.
"If the duplicate host is different from the primary host, then you must make backups and copies on the primary host disks available to the remote node with the same full path name as in the primary database." --- This is the extract from the above doc, which i can't implement.