Laptops use X-Spring keys. Those are not designed to be removed from the top, I doubt you would want to access the keyboard from the back.
A key fell off a laptop once and I put it back together but it took quite a long time and it is very delicate.
I wouldn't try to do this on purpose since they are quite easy to damage but it can be done. Just don't lift them off directly.
How did the keys get in the wrong place anyway? Just came out of the box like that?