Red Hat Training

A Red Hat training course is available for Red Hat Enterprise Linux

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

Note

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-rhsm script 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.