>Is there a way to pass the class instead of the reference of this data edit form into the lookup form? This way I can create the form when the user click on "Modify" each time. In fact, I prefer to create the form only when the user click "Modify" since user only need to modify data once in a while.

How about this as a model:

1. Change the lookup form to raise an event when the Modify button is clicked, passing the record details in the event args. Call the event ModifyRecord

2. In the code that creates the lookup form (client code), after the lookup form is created, add an event handler for the ModifyRecord event that calls a method in the client class that creates the correct data entry form and displays the record based on the event args

Will that get you what you want?