Originally Posted by
Presguy
[...] my friend had already confirmed. [...]
Good. Because many Amtrak employees are unfamiliar with the open sleeper ticket, being ticketed together will help avoid confusion.
Originally Posted by
Presguy
[...] I "changed" the reservation to the new fare, and got a partial refund - which was a nice surprise.
Congratulations, both on noting the reduced fare and on getting the partial refund. Some agents want to give a voucher, and some agents want to withhold 25% of the fare difference as a penalty. I'm glad it worked out for you.