Make a Public Function for this:

Function ChangeDate(KeyAscii As Integer, ActiveControl As Control) As
Integer

   Select Case KeyAscii
       Case 43
           If IsDate(ActiveControl) Then
               ActiveControl = ActiveControl + 1
           Else
               ActiveControl = Date()
           End If

           ChangeDate = 0
       Case 45
           If IsDate(ActiveControl) Then
               ActiveControl = ActiveControl - 1
           Else
               ActiveControl = Date()
           End If

           ChangeDate = 0
       Case Else
           ChangeDate = KeyAscii
   End Select

End Function

Then, you'd use the function in any KeyPress event like this:

   KeyAscii = ChangeDate(KeyAscii,Me.ActiveControl)