Hi Doug

There's some code at the following page that attaches a new template to
documents: http://support.microsoft.com/kb/830561. It's not trivial, and not
for the feint-hearted.

However, that code won't update all the styles from the newly-attached
template to the document. You could modify the code to do something like the
code at
http://groups.google.com.au/group/microsoft.public.word.vba.general/browse_frm/t
hread/cc6eca6902554e07/.

However, bear in mind all the caveats at the following:
How to safely update a document's styles from its template without using the
Organizer (and how to make the Tools + Templates and Add-ins dialog safe)
http://www.word.mvps.org/FAQs/MacrosVBA/UpdateStyles.htm

In particular, bulleted and numbered styles generally don't copy properly
and/or are applied inappropriately to the text in the document.

Finally, none of this will copy macros. In the normal course of events, one
does not (and should not) store macros in documents. The following may help
explain:
What is the relationship between a Word document and its template?
http://www.ShaunaKelly.com/word/templaterelations/index.html

and, see
What happens when I attach a new template to my document? or How do I copy
content and settings from a template to a document?"
http://www.ShaunaKelly.com/word/attachtemplate/index.html

Hope this helps.

Shauna Kelly.  Microsoft MVP.
http://www.shaunakelly.com/word