RMAN-06838
Pluggable database string already exists
Cause
A Pluggable database (PDB) is translating to multiple GUIDs. This might happen in one of the following cases: Case 1: If a PDB is dropped and re-created with the same name, then the PDB has two GUIDs. Case 2: If 'pdb1' is renamed to 'pdb1newname' and if 'pdb2' is renamed to 'pdb1', then 'pdb2' has two GUIDs. Case 3: Restore or recover to a restore point or the 'until' SCN might result in same error, if the PDB is dropped or re-created and after the restore point or the 'until' SCN is processed, the same PDB exists but with a different GUID. Case 4: The pluggable database specified in the DUPLICATE command already exists on the clone database.
Action
Specify a different name for the pluggable database and retry the command.