Source : WordNet®

about-face
     n 1: act of pivoting 180 degrees, especially in a military
          formation [syn: {about turn}]
     2: a reversal in attitude or principle or point of view; "an
        about-face on foreign policy" [syn: {volte-face}, {reversal},
         {policy change}]
     v 1: turn, usually 180 degrees
     2: change one's mind and assume the opposite viewpoint