Next to Sun Tzu's The Art of War, the 36 Strategies is the most widely known book on strategy to come out of Asia. Where the Art of War is an almost text book like overview of the subject, the 36 Strategies seeks to instill the idea of strategic thought by means of groups of 6 proverbs for each of 6 types of situations.
#30 is: Make the Host and Guest Exhange Roles.
The idea here is to usurp leadership in a situation where you would normally be subordinate. Another interpretation is to join the opposition, then work against him from within; eventually seizing power.