Not to do a straight upgrade, no.
You would only cancel and take a new one if the new contract price was cheaper than the upgrade price, but you would need to get the new contract first in order to keep your number so you would have 2 contracts running for the first month.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion.
This is not Customer Service so we are unable to help with account specific issues.Currently using:
Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)