Deleted subform keeps reappearing after PDF is save and reopened

I'm using a script to delete subforms.  It works while the PDF is open -- the subform disappears. But after saving and closing the document, then reopening it, the deleted subform reappears.  I duplicated line 2 and I get an error on it because the subform is gone and can no longer be deleted, so I know it's working.  What am I missing?

form1.Subform.occur.min = "0";
form1._Subform.removeInstance(form1.Subform.index);

I have also tried this and it has the same result:

form1.Subform.occur.min = "0";
form1._Subform.removeInstance(0);