I remember getting on #22 one time in Austin to head for Chicago and was booked in Bedroom A, since it was cheaper than the High Bucket Roomettes.
When I got upstairs, the door was Closed but not locked and I entered and there was someone's stuff allover the room and I heard the Shower running.
I backed out, went downstairs and talked with the SCA Reggie( a Good Friend and an Excellent OBS) who said he'd check with the Conductor, that the guy in the Room had upgraded with the Conductor from Coach after boarding in San Antonio.
( this was in the Paper ticket days when most SCAs collected your ticket for the Conductor) .
Since the Famy room was open, he had me put my stuff in there and asked if I wanted Brsakfast since Austin is Last Call for Sleeping Car Passengers.
I went to the Diner, had my usual Continential Breakfast, and after the Taylor stop Reggie came to the Diner and told me the Conductor had done the Upgrade since the Room was showing as "Available" thru Amtrak.com
My ticket was Valid in the #22 Sleeper since this was a non #422 Day and there was just One Revenue Sleeper in the consist.
He told me that the Conductor told him to put me in Bedroom E ( my Personal Favorite) since it was unoccupied as far as St Louis and something could be worked out then.
I happily took my stuff from the Family Bedroom to the E Room, and it ended up that I got to stay in E all the way to Chicago since the Person booked from STL to CHI Cancelled.
Once I was in Chicago, I called Custimer Relations and they told me that somehow the Computer had Cancelled my A Room Reservation and assigned me to the Family Room Bedroom without my receiving any noticed from Amtrak .
They offered a $200 Goodwill Voucher, but I declined since I actually came out better all things considered.
Only time in 50+ Years of riding Amtrak this has happened to me.( I have had my Room changed but always received advance notice)