My sim only 12 month contract is ending next month and I have found a cheaper one on O2 that I would like to change to.
I would like to keep my number and move that across to the new contract.
How do I go about ending my current contract after I get my final bill next month and how do I then move my current number across to the new sim card?
No need to cancel.
Just go to upgrade in your MyO2 http://www.o2.co.uk/myo2 and choose the new tariff.
Everything will switch over automatically.
Follow the advice here and just choose UPGRADE option
Veritas Numquam Perit
The deal is from uswitch website so it's not actually in the options on the upgrade section of MyO2
Does the same process apply?
In that case, you need to get the new sim deal from uswitch then call O2 to migrate your number to the new contract.
Doing the number migration will automatically end your old contract.
Guide: Coronavirus Community Help and Support for contact numbers.