First, I tried on the cardigan and decided how much I needed to cut off. I decided 7 inches was good. I wanted to keep the bottom band to re-sew onto the portion I cut off, so since that measures 4″, I cut off at 11″.
So it looks like this:Take the 4″ band and fold over the ends and sew–the part with button holes on one side, and the part with buttons on the other.
Pin together and sew about 1/4″-1/2″ seam. I didn’t even finish my edges off. It wasn’t fraying bad at all, so I figured it’ll be fine.