Transfer to a cheaper equiv deal than I have now

There are cheaper deals for 35gb than mine right now online through a website with 1-4 months and then goes to the regular monthly.
Anyone ideas how I do this without having to keep cancelling and starting again ?

Unfortunately only for new customers you would need to port out and come back

Unfortunately you will have to do what is known as a triangle port, which involves basically transferring your number out to a different network, then transferring it back in on the new SIM card.
it is a royal pain but it will only take about 3 to 4 working days. If you start it on Monday