You need to take out the small round fiat cap on the back of the key fob, so you could split the key fob casing in two. Then I think you could just pull out the blade. Got to be very carefull when detaching the fiat cap so you don't damage it. Also when you open the key fob, do it on the table so you can't drop it or something like that. Inside contains a fragile transmitter that comunicates with the car computer sending the key code so you can start your car. If you damage it the key will become useless.
Good luck