If you have a look at the video below, the range 10:30 — 28:25 covers partial regeneration extensively.
Also, with "Auto fix sour notes" that works on a track-by-track basis so if another track had the modified chord, that would still be heard.
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Thanks Noel that video looks very useful.
For the fix sour notes, I had only selected the problem track, nothing else.
I just tried selective regeneration. And while I was able to get a pure G7 eventually,
it didn't last long. As I said the section repeats, and on the repeat the G7 was back to being altered.
So now the question becomes, "How do you do selective regeneration on two bars that repeat and have the regeneration stick with the
1st pass and the repeat?"