Originally Posted by
fransknorge
Is your ticket a Sparpreis or a Flexpreis ?
A Flexpreis is flexible and is valid for all trains on the day of departure, irrespective of delays/cancellations, etc..
A Sparpreis is bound to the train you bought, if the trains is cancelled or delayed more than 20 minutes, it becomes flexible. In this case, well, your trains is cancelled but replaced by one exactly at the same time. So in theory I think you can change trains if you have a Sparpreis ticket. But if it was me I would not do it, I am not sure that would actually be allowed.
If the new train has the same number, OP has to take what they originally booked. The train shown on their ticket is running exactly as booked. If the new train has a different number, then they can take whatever train they want.