How to drop RMAN catalog

The drop command has to be run twice to drop RMAN catalog, i.e. (replace RMANDB with the
database where you have RMAN schema installed):

rman catalog rman/rman@RMANDB

Recovery Manager: Release 10.2.0.4.0 - Production on Tue Oct 7 13:55:42 2008

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connected to recovery catalog database

RMAN> drop catalog;

recovery catalog owner is RMAN
enter DROP CATALOG command again to confirm catalog removal

RMAN> drop catalog;

recovery catalog dropped