Instructions on removing the iPhone from iCloud before sending the device to Property Control.
1. Go to https://www.icloud.com
2. Login with your Apple ID
3. On the main menu select 'Find Phone'
4. It will request that you login again with the same credentials
5. At the top-middle of the page, click on the 'All Device' drop down
6. Click the device that you are looking to remove form your account
7. Select 'Remove from Account'
8. On the next screen, click 'Remove'
After these steps have been completed you should be able to factory reset the IOS device through iTunes or Wifi