I can't answer about what Republic has currently, but a SAP is essentially a "schedule adjustment period". It allows line holders to adjust their schedules to their liking after they have received their initial bid award. You can drop, swap, and pick up almost anything you want. It's first come first serve but I almost always get what I want with my airline's SAP. Not everyone has them, not everyone who has a SAP has one that works well, and those who do, love it. I wouldn't even trade a $20 /hour raise in exchange for my SAP.