Apple keeps track of iPhone ownership based on the primary Apple ID associated with the phone. If you want to register the iPhone to a new owner, you must associate the phone with another Apple ID. The simplest way to accomplish this is to restore the phone to its factory settings and then set it up as a new phone with a new Apple ID. If you want to preserve the information on the iPhone, however, a better option may be to change the Apple ID stored in the phone's iCloud and iTunes settings.

Change Apple ID Settings

Step 1

Tap "Settings" on the main screen of the iPhone and then tap "iCloud."

Step 2

Scroll to the bottom of the screen. Tap "Delete My Account" and then tap "Delete" to confirm. If you previously enabled the Activation Lock security feature on the phone, you must enter the password for the old Apple ID before you can proceed.

Step 3

Tap "Settings" and then "iCloud" again to sign in with a new Apple ID. Type the information at the top of the screen in the area designated "Account."

Step 4

Return to the main Settings screen and then tap "iTunes & App Store." Tap your Apple ID at the top of the screen and then select "Sign Out."

Step 5

Enter your new Apple ID and password and tap "Sign In." You may be required to enter the old Apple ID password before you can change accounts.

Factory Reset

Step 1

Tap "Settings," "General" and "Reset."

Step 2

Tap "Erase All Content and Settings" and then tap "Erase iPhone" to confirm your selection. The iPhone begins the process, which may take several minutes.

Step 3

Tap "Set Up Your Device" to reconfigure the iPhone with a new Apple ID. If you previously enabled the Activation Lock security feature on the phone, you must enter the password for the old Apple ID before you can proceed.