How do I change network but keep my number?

With all the options on the phone market today the best deals move from network to network and a clever customer will make sure they get the best deal going when they come to upgrading (or even end) their contract. People will also want to keep their number, after all why should you have to change number to get a better deal? Well if you follow this guide you will be able to keep your number AND get the best deal available with out even breaking sweat.

Stage 1
The first step to changing networks whilst keeping your current number is to call your current network provider. You will need to call their customer service department so rather than listing all their numbers here I'd advise looking on the providers network. During your call you will need to request your PAC number.

The PAC number is the short term for "Porting Authorisation Code", which is a 9 digit code (3 letters followed by 6 numbers) that you will need to "port" your number to your new network. You are legally entitled to this number free of charge and you should receive it either by text or over the phone almost instantly. Though note at this point that you will need to do the next stage within 30 days of receiving your PAC.

Stage 2
Now you will need to contact the network you are wishing to move to. You will need to arrange your contract or deal with them at this stage so make sure you are getting a better deal than the one you were on and also mention you are wanting to "port" or "keep" your current number. When you mention you are wanting to retain your number they should ask if you have your PAC number, you will be asked to provide them with it.

If you've gone into the store and sorted your new deal out they may give you a temporary number whilst they port your number (should only take 1 or 2 days) if however you've done your deal over the internet or the phone you may need to call the customer services of the new network.

Example
Lets say you were with Orange and you wished to leave them at the end of your contract to go to 3 contract. At the end of your contract with Orange you would call their customer services (either 150 or 450 depending on if you are on a contract or PAYG) and request your PAC. Next you would sort out your new deal with 3 and wait for the handset to arrive. When you receive your 3 handset you would call 3 (dial 333 from the phone) and give them the PAC for them to port your phone over and you'll be sorted out within 3 days (typically 24 hours).