[susan53]

Can I just say that, as the examples from the concordancers showed, "have a change of mind " is used quite often. As always, never trust your intuition on language - always check with data. Intuitively, I rejected it initially too - but when I checked, there it is in lots of examples.

From intuition alone I do agree with PJB - the example s/he gives seems perfectly possible. But have to say that I didn't find any examples in the data - so I would suggest that in frequency at least it's usually positive to negative.