A weaselling we will go
FFS, when will they ever learn. We cannot renegotiate the Lisbon Treaty (there are no provisions within it to do so.
We can only withdraw and then, if the British voters wish we can re-enter under new terms. (see Vienna Convention on the Laws of Treaties (the UK is signatory))
We can only withdraw from EU using Article 50 of the Lisbon Treaty.
Any other argument is deception and no form of weasel words can change that.