I'm not sure I have fully understood, but
a. you can stop Word using smart quotes in the first place by unchecking
the relevant option in Tools|Autocorrect|"Autoformat" and "Autoformat as you
type", if that is what you want
b. You could record a macro that used Edit|Replace to replace each type of
smart quote with a straight quote. You would need to uncheck the Autoformat
options as above before running this (or perhaps you could record that in
the macro too, and switch them back on again after if that is what you want.
In this case, I would
 - save the file in .doc format first
 - then save as a plain text file and re-open it, because that gets rid of
things such as headers and text boxes that may not be updated correctly with
a simple macro
 - switch off the autoformat options
 - do the find/replace operations
 - switch any required autoformat options back on

Peter Jamieson