Do you have a normal ticket, or a saver ticket? With a normal ticket you already could take any train you wanted on the route, and can even have a break en route. Such tickets are for the route, and good for any service on that route for a whole day. This kinds of tickets are actually the default, and it may well be possible that this is what you have. With a discounted saver ticket you are normally bound to the connection you selected during purchase. However if trains are cancelled or the schedule modified you can of course take other trains to get to your destination. The railways would be breaking the law otherwise. In your case what has happened is that the IC from Basel to Bern is leaving a few minutes earlier, because of engineering work on the line. So with your original intended departure from st. Louis you no longer can reach it. So just take a train half an hour earlier. Trains are mass transit. Those are commuter trains used by people going about their everyday business. You are expected to find your way around the system yourself, and check schedules etc. prior to travel. That is what the mail you got tells you. Your original intended departure is no longer possible, so just find an alternative connection, and use it.