My sister's iPhone had been irreversibly damaged. When she got a new one some time later, she had forgotten her Apple ID's password and created a new one. I managed to reset the password just yesterday, and she'd like to use the old account again, as she's bought many apps with it.
How would changing the account affect all data unrelated to the Apple ID on the phone, like call history and text messages? Are they somehow tied to the account, or can she simply change the account both on the phone and the computer and create a new backup without losing anything*?
* Except the apps from the new account, of course. No problem, she only downloaded free ones.