setting objects to nothing

[vbgladiator]

I have the following code.

Dim obj as SomeDataObject = New SomeDataObject(1) '1 is the id in the database
obj.delete 'will delete the object from the table.

How can I make it so that if delete is called on that object,it will set itself to nothing? I don't want that object to be valid anymore if the Delete method is called.