Wanted to add this to the forums, I was looking for a solution to turn off hyphenation for a textbox but it is unavailable to ChangeGrepPreferences from what I can find. Running a simple Grep Find will work where [0] could be looped through each find. Including but commented out lines of change just for additional context.
app.findGrepPreferences.findWhat = "FIND_TEXT";
app.activeDocument.findGrep()[0].parentStory.hyphenation = false;
//app.changeGrepPreferences.changeTo = "REPLACEMENT_TEXT";
//app.activeDocument.changeGrep();
As an example of normal attribute syntax, below is justification.
app.changeGrepPreferences.justification = Justification.LEFT_ALIGN;
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