Updating to a new Apple ID/Email on Apple account and on iPhone

Hi, I have checked various online questions/tutorials about changing your email and Apple ID. I have followed the instructions to update the email/ID on the web by going to appleid.apple.com, and completed that process. However, my iphone then would not allow me to get to the email address in the iphone settings, it would just say "Verifying", which it apparently could not do, since the I changed the email address/apple ID online (so I changed it back for now). Question is, if you change your Apple ID online because you soon will no longer be using (or have access to) that particular email, how do you synch your phone to the new email address/Apple ID? I seem to be missing something in these instructions that allows you to synch the phone to the new email address/Apple ID after it is changed online.