I cut the dress under its elastic waistband, and cut off a section of fabric to create the waistband. I undid part of the side seam and put in a zipper. This was done not as cleanly as I would have liked. The seam allowance was only at about a quarter inch, so I didn’t sew through all the fabric when I put in the zipper. So I hand sewed the fabric that didn’t catch, which made it rather sloppy. But I was just too lazy to redo it. I gathered the top of the skirt and then sewed the waistband to it.
Overall, it didn’t take as long as starting from scratch, but isn’t something I feel super excited about. It’s a fine skirt, wearable, but not something I love.