A Recast is a Leader that has been cloned from another leader. Recasts offer a way to quickly modify or innovate on someone else’s Leader Formula. For example, let’s say you are looking at a leader system that says it is intended to be fished in water depths between 5-8 feet. Overall you like this setup, but it is too short for the water you fish around your area. You can Recast that Leader, load it up into the Builder, adjust the length to your own specifications (leaving the rest as is), and save it as a brand new Formula - all with just a few clicks.
You can see an example of a Recast here.