The only "true" way is to remove the skin. But, just a thought... if you feel the need to give the directions on how to do this to the vinyl repair shop, then look for another shop. This is not rocket science for anyone that does this even somewhat regularly, so they shouldn't need help. How's the rest of the vinyl - is it still soft and worthy of repair? If it's on it's last legs, it may not be worth paying for a repair as it won't hold the thread, anyways, and will rip back out in short time. In that case, put some reinforcing tape on the vinyl and just stitch it up without removing for the time being, or maybe just tape alone over the seam.
