turnabout

Short definition from Wiktionary

Noun

1. 1
   The act of turning about so as to face in the opposite direction.
2. 2
   A change from one thing to its opposite, or from a situation to the reverse.
3. 3
   A reversal of a decision or opinion etc; a change of mind or flip-flop.
4. 4
   A merry-go-round.