1. Use a small screwdriver to pry the lamp out on the side it has a small slot in the black plastic case (in my LHD car it was on the right side for both lamps);
2. Pull the lamp out;
3. On one side it has a sort of white plastic clip, push it and the lens will be released;
4. Change the bulb;
5. Do all the things in reverse to fit it back.
Be careful, the licence plate lamps are very fragile. If you break one clip glue the lens to the case or the case to the bumper.
~Nautilus