I found this maternity dress for my sister at a garage sale and it turned out she already had one exactly like it! So she said I could keep it to make something with.
I took the bodice off the dress and then took off the first tier of the skirt. Out of that tier I cut a yoga-style waistband. I followed these instructions, only mine doesn't fold over because I didn't have enough fabric. Then I gathered the skirt and stitched my waistband onto it. It is definitely my most comfortable skirt!