I've never embroidered jeans before, but I was browsing Urban Threads and saw the tutorial about how to do pockets. I thought they had a really good idea about not unpicking the whole pocket. (Just leave a few stitches attached at the top.) The rest of the method looked a bit clumsy to me. I chose my design and stitched the built in baste on my machine onto stabiliser. I positioned the pocket over it and stitched it again.

To redo the top stitching, I picked an embroidery thread as close to the original as possible and wound some off onto a bobbin. I threaded the machine up with double thread and stitched the pocket back on (increasing the stitch size.) I used the rest of the double thread to shorten the legs.