SpaceX Crew-9 dropped 2 NASA astronauts from ISS mission, but they were prepared (video) 

 Only 2 astronauts will launch to the ISS Sept. 26 with SpaceX instead of the planned 4. We spoke with the crew before the big change was made. 

https://cdn.mos.cms.futurecdn.net/R6QpUXpV6S4EPAmLpwhsUL.jpg

https://www.space.com/nasa-crew-9-ready-for-launch-spacex-falcon-9-failure