Changing your primary domain is not something that can be done at the client level at this point in time!
The default design of cPanel/WHM doesn't allow us to change the primary domain directly. We need to delete your existing hosting account and create a new one with your new domain. This process involves data loss.
If you still want the primary domain change, please email hosting@ibraininc.com or open a ticket saying "I want a primary domain name change for <your-new-domain-here>. I acknowledge that changing my primary domain involves data loss."