From my experience when I switch to FIZZ from my previous provider, I ask Fizz if they can keep my number. They said yes, then I gave all the information they needed for the transfer. When the transfer is completely done, I can finally cancel the service with my previous provider.
Hello! Not all companies allow a number transfer. You’ll have to check with the company before!
If you are switching from Fizz to another provider, you should ask your new provider. Is your old phone number still active? Don't cancel your old phone contract until you port over the number.
Usually, it's the provider that you are going to that handles cancelling your current provider.