Purchase a new seam ripper, one with a tiny blade. Very gently take out one or two threads at a time. It is almost impossible to tear out the stitches from the top. Honestly, I have never had success ripping out stitches from the front without ripping the fabric. There will be a ton of holes and they won't go away no matter how much ironing and steam you use. The fabric will be a bit thinner also. You would still need to put an appliqué over it.