1. From you Blogger dashboard, click the drop down menu and select "Settings."
2. Once on the Settings page, select "add authors." Be sure to enter the new email address.
3. Login with the account you want to use, accept the invitation, then logout.
4. Login to your old account and upgrade the new account to an admin, then logout.
5. Login with your new account, go to the Blogger settings and delete your old account's email address, then logout.
6. Login with your new address to see if it works. Hopefully it should.
I don't know why Google doesn't make this information readily available, but I hope this helps if you're in the same situation I was.
*Note: An easier way to do this, I later found out is to do this with two different browsers, i.e Firefox and Chrome, to keep from logging in and out.