[Adoby]

When you add books or documents to calibre, a copy of the book or document is stored in calibre.

If you edit the original document, then the copy inside calibre is not updated. You have to edit the original and add it to calibre again, and possibly delete the old copy. If you no longer has the original document available you can save the copy in calibre to disk, edit it and add the edited copy back to calibre. If you are very careful and know exactly what you are doing you could also edit the copy in situ inside the calibre library.