When Emerald initially canceled our Danube cruise, they simply mentioned that it had been "postponed" with no details on exactly what that meant, whether another date had been identified, or any other details. Since this was our first cruise, I didn't know enough to know which questions to ask. Once we spoke to our travel partners, we (head-slap moment) realized we should just call up and ask specifically what our options are. Once we did so, we got a lot of helpful info and found a Rhine cruise for the same dates that worked for us.
It would seem like the Scenic/Emerald customer service staff are not trained sufficiently to transition the trip-canceled conversation to discussions about options. One would think that would be Customer Service 101, but I'm sensitive to the fact that everybody is having trouble filling jobs and that some of the training and experience are probably lacking as a result.