How do i delete/remove/hide a system/staff?

I'm working on an SATB choir arrangement. I used the Piano + SATB template when creating my new document. Part way through the process, I decided I wanted a 5th staff for a descant, added the staff and named it Descant. I decided I didn't need the descant part after all, and can't figure out how to get rid of it. I've also decided that I DON'T want to transcribe and print the piano part...just the vocal parts (I'm creating the SATB from an existing tune written as a solo, and will just have the accompanist read from the solo version). How do I get rid of the staffs/Systems I no longer want?