The page at
https://www.amtrak.com/planning-book...on-policy.html says the following.
Subject to applicable cancellation policies, all fares are non-refundable and non-changeable after departure. Passengers who “no show” or do not cancel prior to departure forfeit the entire value of their “no show” segment. This policy applies to tickets paid in USD (including via Gift Certificate) as well as tickets paid with Amtrak Guest Rewards points.
I don't understand what Amtrak means by "Subject to applicable cancellation policies". I found no fare that mentioned a cancellation policy that deviated from the No Show policy, but multiple people have taught me that my reading comprehension skills have declined.