Thanks ACL,

My question on a more specific level was, once a trip had been assigned to a long call pilot on the day prior (more than 12 hours), can an out-of-base white slip legally come and decide to take the trip from a RES pilot after it has been assigned later in the day (but still 12 hours from report)

Scheduler tried to pull a trip after they assigned it to me, and I queried the scheduler about it and I got the trip back. I was just curious because it seemed unusual. I realize a white slip has first dibs on a trip, but I didn't think a trip could be pulled like that after it has been assigned.