Threaded comments/ revert to Notes

I'm using Excel 2013 for spreadsheets with a large number of Comments (Notes).  A workbook saved on OneDrive required me to select threaded comments to edit comments I had saved as Notes, with the result that ALL of my comments were converted to "threaded comments".  I want to revert the comments in the entire spreadsheet to Notes (the legacy format).  How can I do that?