I finished that skirt. Of course, it could not have been as easy as I thought. I stitched on an elastic casing made of purchased bias tape - with the ends folded under - and inserted the elastic. When I tried it on, I decided that I needed to narrow the skirt a bit.
After figuring out how much I needed to cut off, I laid the skirt out on the cutting table and just hacked it off. I ripped out the casing's lower edge of stitching for about three inches to each side of the cut. I opened up the casing, pinned the cut edges right sides together, and stitched the seam. I followed this by zigzagging over the cut edges. I turned down the casing and stitched it down along the lower edge.
Have you ever had to undo the work you've done on a project?