Using Excel & Word 2003.

I have a spreadsheet that contains a lists of part numbers. Each part
number has a corresponding Word document. Currently I have Excel open
that document in Word. A Word macro checks the value in a table's cell
and if the cell is blank, enters "A" and then saves the document. What
I need to program in now is if this happens to write the part number in
a different spreadsheet (same workbook) in Excel. I can't seem to
figure out how to send a variable from Word to Excel.

Can anyone help me out? Thanks a bunch.