On the menu go to Tools, Database Utilities, Linked Table Manager. It should
say to where the tables are linked. Don't make any changes here. Just hit the
Cancel button.
Get everyone out of the database before making any changes and do a full
backup first of the FE and BE files. Also it's possible that the linked
tables aren't even in an Access database.
By programmer being gone, I assuming that you mean permenently. If you are
just a beginner with Access I'd be very careful before adding a field. It's
slightly possible that adding a field will break something such as an append
query.
Also the new field might not really be needed or already in another table
with a relationship to the table that you want to modify.