There are no instructions in the owners manual and I cannot find any information online regarding how this is done. I found one site that refers to a Toyota RAV where they say they can only replace the rubber part of the wiper and not the entire blade.
This is really easy. You can get the replacement blade at Kragen Auto, it is rear wiper 12A.
From there, the first thing you need to do is remove the cap on the part attached to the car. It is shaped like a U. Pull out on the legs of the U, this pulls little plastic pins out of the holes used to secure them. Then lift the piece towards you. The cap should come off.
Now bend the wiper arm towards you. Grasp the blade and continue pulling towards you. You should hear/feel a pop then the blade will came off a C shaped holder.
Place the new blade on the C shaped holder and push in the opposite direction to place back on the wiper arm.