Complex sentence: Walter Plinge is a pseudonym, traditionally used in London theatres when a part has not been cast, an actor is playing two parts or an actor does not want his or her name in the programme.
Split into simpler sentences: Walter Plinge is a pseudonym, traditionally used in London theatres. The name Walter Plinge is used in London theatre when a part has not been cast, an actor is playing two parts or an actor does not want his or her name in the programme.