something like this ...
In the onChange event of the BlanketPO
field, add something like this (make sure in designer, in the infobox of
the BlanketPO field, Run Exiting/OnChange events after the value
change is selected
Dim uiws As New NotesUIWorkspace, uidoc
As NotesUIDocument, sPO As String
Set
uidoc = uiws.CurrentDocument
sPO
= uidoc.FieldGetText("BlanketPO")
If
sPO = uidoc.FieldGetText("BlanketPODsp") Then
uidoc.FieldSetText "BlanketPO",
""
uidoc.Refresh
End
If