First off I am using access 2000. I have a form where the user is supposed to enter expense lines for a truck fleet. Some of these expense lines may have POs some may not. In the form there is a subform. The parent form is an expense line header (contains invoice number, total cost, vehicle, etc.) while the subform is the actual expense lines which may have different expense accounts these should sum to the total for the invoice. In the header form I have a button that opens a modal form with a list box containing any currently open PO lines for that vehicle. The user can pick which lines to enter as expenses and then the selected lines need to go to the expense lines subform. I'm planning on moving the information for each PO line to the subform by writing an append query to write partial records to the expense lines table and then requerying the subform to get access to those newly written records and then allow the user to enter any remaining info. Whew lot of background to get to this. I then need to validate the information in the expense lines subform. Is there a single event to make sure all the entered info is there say when I navigate away from the parent record. Or is there a better way to arrange this mess. Any comments appreciated. Thanks