05-01-2018 08:10 PM - edited 05-01-2018 08:11 PM
if your daughter had this phone from EE after 1 st September 2015 then it should be unlocked automatically after 18 months.
For more details please have look on above link.
05-01-2018 09:19 PM
Your daughter can just apply using the Unlocking your device form as the Pay Monthly option and giving the mobile number that it used to have. It will first show her current phone on that number & ask whether that is the device you want to unlock? If not, she will then have to type in the IMEI of the old phone.