As I don't use Mac Word, I can only advise on the basis of what I see in Win Word. So, the way you need to access some of the features might differ.

First, after the last Section's contents, but before the endnotes begin, insert a new Section break. For example, if you have an 'Endnotes' heading, insert the Section break after that.

Next, change your endnote setup from 'End of document' to 'End of section'. Make sure the numbering is also set to 'continuous' rather than 're-start' for the whole document. To make these changes, you will need to access the footnotes/endnotes menu. In Word 2003 & earlier, that's done via Insert>Reference>Footnote. In Word 2007 & later, it's done via References>Footnotes. For the moment, this will cause all of your endnotes to relocate to the ends of their respective Sections.

Finally, select Sections before the last one (i.e. not including the Section with your 'Endnotes' heading), then use the Page Layout>Page Setup tools to access the 'Suppress endnotes' option and check it. In Word 2003 & earlier, that's done via File>Page Setup>Layout. In Word 2007 & later, it's done via Page Layout>Page Setup>Layout. Your endnotes should now appear back where they were before. Any content you now insert into the body of the document after the final Section break will appear after the endnotes.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]