I set up an email account name when I setup my account, but now I decided that I don't want that account to be the account name that my emails come from.  So I've tried setting up new accounts, users etc.  No matter what I do, that email account just keeps showing up as the default account that I'm logged into Mail with and that all my emails seem to be coming from.  I'm OK with that account existing, but I just want my email to come from a different user email address.  I tried changing the "primary" account, but that didn't make a difference.