If you mean in advance, no. The trips that are in open time can be picked up or traded by line holders up until the morning before. The morning before scheduling assigns trips to reserve pilots and thats when a reserve pilot can request which trips they'd prefer to fly if they have to fly.

Its kind of like bidding and first dibs go to the pilot with the lowest raw who is next up. But just like everything if you're available for four days they're not going to give you a day trip or two-day, you get to pick one of the four day trips and if there are no 4-days, and they have sufficient coverage, then you probably get short call or nothing because they're saving you for a 4-day if one pops up. I think they'd have to be very desperate to allow you to do anything less than a 4-day if you're available for 4 days.

Otherwise, the rest of the time is just saying you're willing to come in and fly on your day off for any trip (or any trip that meets parameters or for only a specific trip) that pops up same day or is open time for the next.

Its all spelled out in the PWA and they just go right down the rules in there as they assign trips.