Thanks! That worked; most helpful!

Is there an example out there to demonstrate this? I created two queries: one showing tables without assignees and another that included the two tables that then displayed only those individuals unassigned. How to automatically link this in a datasheet view is leaving me stumped.
UPDATE: The dropdown I have works in the query mode but there is not an option to apply an action. I have to hit the F5 key every time I enter the new value. ...

I have two tables: attendee and seating.
The seating table has the fields:
[TableID], [Tablenum], [Seatnum], [AssignID]
As tables are set up, the records for each seat are populated in the seating table.

This is for a fundraiser where the amount of tables that are set up will depend on the number of attendees that preregister and the possibility of others showing up the night of the event. The more people, the...