How to change primary email address?

I'm writing this for my son. He wants to change his current email address to his secondary account, and make his new email address as his primary account. Is there a phone number where he can talk to a live customer service person? Or, can someone explain this in easy to understand language? He has gone to the help section, and is still having problems. He's getting too frustrated to continue this on his own. So, I am trying to help him. You can email me at logcabin1999@yahoo.com Thanks, Judy