How can I change my iTunes Account Name to something different from my Billing Information Name?

I have this same question as a parent. We used our credit card for son's account many years ago. We used his email. He is grown now and we want to change the name on the account to him, keeping the same email. I have no idea how to do it.

If you log into the account (e.g. via the Account > View Account menu option on a computer's iTunes ; Store > View Account on older versions of iTunes) and select the payment details section of the account you should be able to update the billing name and address