Public myValue, mAddress As String
Private Sub Worksheet_Change(ByVal Target As Range)
If MsgBox("Click Yes to revert to original value", vbYesNo) = vbYes Then
If Target.Address = mAddress Then
Application.EnableEvents = False
Target.Value = myValue
Application.EnableEvents = True
End If
End If
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
mAddress = Target.Address
myValue = Target.Value
End Sub