[CentOS] CentOS upgrade info

Mon Feb 16 11:38:00 UTC 2015
Jegadeesh Kumar <jegasmile at yahoo.com>

 Hello,
I wan to know the details steps about how to do OS upgrade?
Say for an example currently i am using CentOS 6.2 and plan to upgrade that to 7. Please detail me the steps.

Thanks,
Jegadeesh