ON A COPY – (actually endnote may force you to make a copy) on the endnote ribbon, choose the “convert citations and bibliography” (then from dropdown) “Convert to plain text”.
(added in edit) or you can (and you must do this on a copy, not on the original, which you will want to keep if you have corrections and then redo these steps) use Word tools to remove ALL fields, including table of contents, etc by ctrl+shift+F9 .