Remove Phone from Apple ID
1. Go to https://www.icloud.com/find/
2. If you don't remember your password, click "Forgot Apple ID or password?" and go through the steps to recover it
3. Log in and click All Devices at the top
4. Find your work phone and click on it.
5. Click Erase iPhone
(Because the device isn’t lost, don’t enter a phone number or message. If the device is offline, the remote erase begins the next time it’s online. You receive an email when the device is erased.)
6. When the device is erased, click Remove from Account.
7. All your content is erased, and IT can now reuse or recycle your cell phone