Most people that I know (admittedly not a scientific sample) still retain their Leave or Remain position's, in fact most are even more entrenched in their views, if that was possible! Of course people change their minds, but usually after the effects of their decisions have been felt, i.e. 'byers remorse' etc.
There is no real evidence that large numbers of people (i.e. enough to give a larger overall majority one way or the other) have changed their minds about leaving or remaining. We were given a binary choice on this matter, by Parliament, to remain or leave nothing can undo that result. The question is will the MP's enact this mandate or will they not... to be honest I suspect either way the next decade will change the face of British politics forever... or until a new referendum is called, that is if any future Government is silly enough to try!