38.2. Systems Registered with RHN Classic
There is no command to specifically unregister a system which is registered with RHN Classic. To delete the registration locally, remove the file with the system ID assigned to the system when it was registered:
[root@server ~]# rm -rf /etc/sysconfig/rhn/systemid
If the system is being unregistered in order to register it with Red Hat Subscription Management (Customer Portal Subscription Management, Subscription Asset Manager, or CloudForms System Engine), then instead of unregistering the system, use the
rhn-migrate-classic-to-rhsmscript to migrate the system and all its attached subscriptions to the specified Red Hat Subscription Management server.
Using the migration scripts is covered in the Subscription Management Guide.