I'm still in the same contract, so locked in until next April. But thats fine by me, because I only have me desire a little while and no plans on moving networks. Also, it was left a bit ambiguous, but am fairly certain that I can get an upgrade in a while if i wish.
I didn't have to do a thing. She just applied everything there and then (or so I'm told). I'm on the bill pay lite price, with bill pay lite add ons (i.e. free meteors), but just still have the same contract term. More than happy with that!
Now if you want to be free of the 18 month term, then I reckon you will need to cancel and move to PAYG, then switch to Bill pay lite in store.
Of course, if you only want to get out of the term so you can upgrade in a little while, you can do what i did. What she did was add a note to the system saying I can have one if i want. Something similar was done before, so I know it should work if go in store to buy down the line.
I didn't really push that point to hard, because its not a big deal to me at the moment, seeing as I only have my phone 3 months. Won't want another for a wee while yet!