BOGO sleeper sale on previous tickets?

[cathands]

I bought roomette tickets on the Coast Starlight for my boyfriend and I, and two days after I paid they started up the BOGO sleeper sale. I doubt I'd get anywhere if I called reservations and tried to get the discount applied to previously purchased tickets, but would I be looking at any kind of penalty if I cancelled his ticket and rebooked to get the sale? It's part of a multi-city trip if that makes any difference, but he's only joining me for the Coast Starlight portion.

 

[Entchen]

I actually just did this to have a friend join me for a California Zephyr trip I have booked for September (sort of - my situation was a bit different in that I originally booked to travel alone, and then my friend decided to join me when the sale took effect, but close enough). There's no cancellation fee if the reservation is more than 120 days away. I bought at the lowest bucket price, and by the time I tried to re-book, it had gone up to the 2nd bucket, but that still would have been cheaper than buying my friend's ticket separately. As it turns out, cancelling my reservation pushed the price back down to the lowest bucket, so I ended up just getting the additional ticket for no extra charge.