If you are stranger to replace sunglasses lenses, you'd better have an optician to do it for you. Or, you may get your finger hurt even break or scratches your sunglasses lenses. Anyway, if you want to do it yourself, you shall first prepare a screwdriver that specially for sunglasses or eyeglasses. Then, use it to loose screw before take the lenses off.
You'd better let the professional workers in the glasses store do it because they may use the professional machine to wash your clear lenses and do it by a little polish to make it look perfect. However, if you insist on doing it by yourself, you should firstly make the ray ban sunglasses put into the high temperature which may make the lenses easily to be taken off. Then you can change them by yourself.