Senior pilots will be called after a junior pilot having the same number of days of reserve left have been used; assuming both pilots are under or at guarantee still.

If a senior pilot wants to fly, they can make themselves as “call me first” and they will be called before the junior, but you can’t just turn it down if you don’t like it at that point.

There are more complexities with it all but basically if 2 guys have 3 days of availability and a trip comes up and fits in both guys RAPs, junior gets the assignment. But like I said, a few complexities to it