Pretty Providence says: I did not alter the waist at all. Just the legs from mid-thigh down to the bottom….All I did was turn the white pants inside-out, lay a pair of skinny jeans I had that fit well on top of them. I pinned the white ones right on the line of the inside where I wanted to sew them up. I sewed the straight line along where I had pinned. Then cut the excess fabric off, and they were skinny.