Hah. Amtrak rules, airlines.
First off, when you change to a cheaper train you get a refund. And there is no change fee.
But more than that, in the past half year I've accumulated enough points to go to New York twice. And was able to book the trains I wanted, on the dates I wanted, quite simply and with no hoops. Just put in 'use points'.
I love the train. I have always loved trains, but I really love it here in the Northeast Corridor.