🚀 go-pugleaf

OK, you're confusing how the UI works with how scripts work. You don't need to "select the text" but rather reference each instance.

A scripted Find will do the job. Something like this:

if (app.documents.length == 0) { exit() }

aDoc = app.activeDocument;
myStyle = aDoc.paragraphStyles.item("BodyText"); // Use your style name
app.findPreferences = null;
app.changePreferences = null;
app.findPreferences.appliedParagraphStyle = myStyle;
myFinds = aDoc.search("",false,false,undefined);
for (j = 0; myFinds.length > j; j++) {
	myFinds[j].appliedParagraphStyle = myStyle;
}

It's interesting that if you just do a Find/Change with myStyle set as the app.changePreferences.appliedParagraphStyle, nothing happens, but applying the style to each found instance, as I've done here, will eliminate local styling while preserving character styling.

Not clear if that is actually what you wanted to do.

Dave