backout the kernel patch on Redhat

How to backout already installed patch.
I upgraded the server from RHEL 6.3 to RHEL 6.6 and I had to back it out to the old one. And upgrade it to RHEL 6.5. This is how it was done.

[root@sama ~]# yum history
Loaded plugins: product-id, refresh-packagekit, rhnplugin, security,
              : subscription-manager
This system is receiving updates from RHN Classic or RHN Satellite.
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
     2 | Dev  <dev>    | 2015-02-02 14:20 | I, O, U        |  497 E<
     1 | System <unset>           | 2013-02-22 10:14 | Install        |  878 >
history list

Now, you can either do  "yum history undo last"  or  "yum history undo 2"  based on the output above.

[root@sama ~]# yum history undo last

Once removal is completed. Reboot the system and run the upgrade. Remember to do "yum clean all" before "yum update"
# yum clean all

Register the key
# rhnreg_ks --activationkey=your-key  --serverUrl https://your_server/abc --force

# yum update

once completed, reboot and again register with new channel and update to correct version.