Two iPhone 4S Configured with same email ID I had a iPhone 4S which was setup with a Gmail ID and later I returned it to my employer, since it was given by them. I have a new personal iPhone configured with same email id.

When my employer tries to configure old phone for somebody else, they face an issue that device is mapped to my Gmail ID. They are unable to configure it for new person.

What can be done to resolve issue?
In your former iPhone:


Tap Settings > iCloud. Scroll down and tap Sign Out. In iOS 7 or earlier, tap Delete Account.
Go to Settings > General > Reset > Erase All Contents and Settings. 



  In iOS 7 or later with Find My iPhone turned on, you'll need your
  Apple ID and password.


Additionally, 


  if you're using iCloud and Find My iPhone on the device, sign in to
  icloud.com/find, select the device, and click Erase. After the device
  has been erased, click Remove from Account.


Get your former employer to set up the old iPhone with other Apple ID.

Check this article on Apple Support for more information.