I loaned an old iPhone to friend until they bought a new one.

I had an iPhone 5 that I wasn't using. A friend had an iPhone 5 that just quit, so I loaned it to her for a couple of months and the iPhone 5 was being discontinued. I did not clear out my user id from the phone. When she finally purchased a new iPhone from the iPhone store they set it all up for her, but it also has my ID in her new phone. Every time she gets an update it always notifies my ID of the update not hers. I looked around inside and didn't see my ID only hers.

I would very much appreciate any ideas on how I can get myself out of her new phone.

Thanks for all your help.