I purchased a (Flex) Thalys Train ticket from Rotterdam leaving after our cruise. I know with the flex policy you're allowed 1 change without penalty. There is a chance we will make it off the ship in time for a train that leaves 2 hours earlier, but I wanted to pad our time because of previous hectic disembarkation experiences. If we were to make it to the station to catch the earlier train, would they allow me to take that earlier train the "day of"? Or would I have to give more advanced notice?