By turning that wish into a goal
There are lots of charities who will do this sort of thing.
No, Thats kind of a trick question. If something is impossible it is not feasible to assume it can be overcome. Overturn your original question into "Can a wish that seems impossible be granted?"
Try going to www.real-wishes.com. I am doing it right now, and it is pretty cool. It's free, you don't need to give any information, and it makes your wishes come true!! It is REALLY awesome.