I'm not sure if I'm understanding the question correctly, so this reply
might be totally irrelevant.
Have you typed the citations directly into Word, not using the "Insert
Citation" "Add New Source..." dialog? If so, then no, there is no way to
automatically export them to a master list. Word cannot guess the format you
used. Your only option is to copy/paste them between documents or create
sources through the "Add New Source..." dialog and fill in the different
fields manually.
Have you entered your citations through the "Add New Source..." dialog? If
so, they should already be in your master list. To check if they are there,
use the "Manage Sources" button and check the left column. If they aren't in
that column, you can use the copy button to copy them from the right column
(your document).
Now if you create a new document, you can once again click "Manage Sources"
and select the sources in the master list (left column) you want to use in
your new document (right column).
Yves