as I said before, I am not trying to unlock the message, I am trying to bring back the date to a date earlier than the lock date so as to make the machine will become operational again with the same locking conditions set by the machine tool builder
so my question is... am I able to modify the date in this case or not ?
Back up your ladder and go into the BOOT mode and delete the ladder file, then your controller will BOOT without the ladder so IF the ladder is doing it you will be able to change the date. IF the ladder is not then you won't.