Are you talking about dropping trips once you get them while on Reserve? No, that is not a thing. Is it anywhere?

If you are talking about when you get a line it is highly dependent on bid status and seniority. i.e., you're going to have crappy low time trips over the weekends and coverage days that you will either be unable to drop/trade or nobody will want them. AA is probably the most "you only get QOL through Seniority" airlines out there. Be prepared for that.