As a built in security feature, Apple requires that you turn off Find My iPhone before resetting the device, or sending it in to Apple for service. This requires you to enter your Apple ID password to confirm that you are the rightful owner.
Please proceed with the steps below to turn off Find My iPhone, iPad, and iPod.
Step 1) Using the built in Settings app, tap on “Mail, and then in the bottom right tap the arrow to the right of “Find My iPhone”. (If you are using iOS 10.2 or earlier, you will tap “iCloud” instead of “Mail”)
Step 2) Toggle the ON/OFF switch next to “Find My iPhone” to the OFF position
Step 3) Enter your Apple ID password and tap “Turn Off”
You will receive an email notifying you that your device has requested that “Turn My iPhone” be turned off. No further action is required if you just did the steps above.
Please comment with any questions.