Excel 2003

I have a list of products in column A and the country of origin for each product in column B. Some of the products are missing the county and some items have an incorrect country. I want to change column B to data validation list drop downs (no problem with this part), but I want to retain the existing country, if there is one, as the shown answer, for each product. At the same time, if there is not currently a country, the drop down would be available to choose from the existing list. Any suggestions on getting an already shown country to show as the answer, but be able to change it if it is wrong. Thanks.