on 17-11-2018 12:43
Go to "Manage my details" in your MyO2 http://www.o2.co.uk/myo2
If you have any problems, call customer services
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)
on 17-11-2018 17:43
Either way you will need to receive a text to your phone for confirmation.