or try this

Private Sub Worksheet_Change(ByVal Target As Range)

   On Error GoTo ws_exit:
   Application.EnableEvents = False
   If Not Intersect(Target, Me.Range("A1:H10")) Is Nothing Then
       With Target
           .Value = DateSerial(Right(.Value, 2), Left(.Value, Len(.Value) -
4), Mid(.Value, Len(.Value) - 3, 2))
       End With
   End If

ws_exit:
   Application.EnableEvents = True
End Sub

'This is worksheet event code, which means that it needs to be
'placed in the appropriate worksheet code module, not a standard
'code module. To do this, right-click on the sheet tab, select
'the View Code option from the menu, and paste the code in.