Hello @Sammielex ,
Welcome to the community,
You should be able to do this by clicking on upgrade, you should then have the possibility, or you can ring customer service and they can do this for you, you may even get a better deal by ringing them.
To contact EE customer service dial 150 from your mobile phone or ring customer service for free using Skype or another phone: +44 800 079 8586 or +44 800 956 6000.
