There is a far simpler solution: Delete all the content and save the empty document as a macro-enabled template (.dotm format). Save the template wherever group templates are stored if you want your macros to be available to the document when your colleagues are using it, otherwise, just save the template to your local templates folder. Having done that, re-open the original document and attach your new template to it. Then save the updated document in the .docx format. Done. Your macros will be available to the document provided its template is also available to it.