I considered several patterns from my stash but finally settled on Simplicity 2605.
The first thing I did was open the side seams. I planned on using the existing hem so left it intact. I also planned to reuse the zipper.
Speaking of the zipper. I've never seen this on a zipper before. The fabric on the botton of the zipper is totally new to me. I don't own a lot of RTW so it could just be me. I think it's really cool.