Turn the extractor until its out of the front guide ring and push it forward from the rear.
Be careful if you have to pry up on it to get it over the lip. Some of them are brittle and break easily.
Put it back together by reversing what you did to take it off. Some of them are extremely tight and may need a rap on the rear with a wooden spoon or something a bit heavier. Don't use a hammer of any sort, unless it has plastic impact faces.
