"changes of opinion" is correct and usable in written English.
It can be used when referring to the act of modifying a previously held opinion. For example, "The student's changes of opinion often caused her trouble in class."
"Don't write off big changes of opinion in second votes in the last few weeks of the campaign," Shafi said.
This can (and has) led to interesting discussions at board level that have resulted in changes of opinion within the charity and the belief that borrowing is bad.
The Labour leader's conversion from critic to champion of the European project has been speedy by the standards of a man not known for promiscuous changes of opinion.
It may be that the scandal, by offering an obvious explanation for the shift, is actually masking changes of opinion which are occurring independently of it.
But with my first book of nonfiction, "Normal," I discovered that changes within me, especially changes of opinion, concerned my subjects as much as, or more than, they did me.
Opinion shifts regarding issues of human sexuality are most obvious, but there have also been significant changes of opinion regarding non-sexual matters.
One scientist encouraging this change of opinion is Dr. Trond Amundsen, a zoologist at the Norwegian University of Science and Technology.
The most important factor contributing to a change of opinion was knowing someone who was LGBTI.
Iran's foreign minister, Manouchehr Mottaki, told state-run radio that Iran welcomed the change of opinion about its nuclear program.
"I don't think this brings us out of the woods yet, but it is a welcome change of opinion from the Fed".
