Yes, it is possible. In a way.
If you talk about using RTE or any other web editor, and dont want to use any data from OpenACS, then you use the HTML to DOC conversion mode offered by OpenOffice, so you install OpenOffice and write a macro that loads the HTML file and saves it as .doc file. Then have OpenACS deliver this back.
Though I'm not sure why you would like to do this in the first place. Usually you would prefer to return PDF documents, wouldn't you? (Why would someone edit a Word document on a Website with limited capabilities when you could use Word in the first place).
On the other hand, if you need to modify data in the document being written, then you need to write a template, fill it with acs tags and then off you go.
