WordNet (r) 3.0 (2006):

turnabout
    n 1: a decision to reverse an earlier decision [syn: reversal,
         change of mind, flip-flop, turnabout, turnaround]
    2: turning in the opposite direction [syn: reversion,
       reverse, reversal, turnabout, turnaround]

Moby Thesaurus II by Grady Ward, 1.0:

141 Moby Thesaurus words for "turnabout":
   about-face, about-turn, accommodation, adaptation, adjustment,
   afterthoughts, alteration, amelioration, apostasy, apostate,
   back track, back trail, backing, backing off, backing out,
   backing up, backslider, backsliding, backup, better thoughts,
   betterment, bolter, break, change, change of heart, change of mind,
   changeableness, collaborationist, collaborator,
   constructive change, continuity, conversion, convert, coward,
   defection, defector, degeneration, degenerative change, deserter,
   deterioration, deviation, difference, discontinuity,
   disenchantment, divergence, diversification, diversion, diversity,
   fifth columnist, fitting, flip, flip-flop, gradual change,
   improvement, lapse, mature judgment, melioration, mitigation,
   modification, modulation, mugwump, overthrow, proselyte,
   qualification, quisling, quitter, radical change, rat, re-creation,
   realignment, recidivation, recidivism, recidivist, reclamation,
   reconversion, recreant, redesign, reform, reformation, regress,
   regression, rehabilitation, reinstatement, relapse, remaking,
   renegade, renegado, renegate, renewal, reshaping, restitution,
   restoration, restructuring, retrocession, retrogradation,
   retrogression, retroversion, return, returning, reversal, reverse,
   reversing, reversion, reversionist, reverting, revival,
   revivification, revolution, revulsion, right-about,
   right-about-face, runagate, schismatic, seceder, secessionist,
   second thoughts, separatist, shift, slipping back, strikebreaker,
   sudden change, swingaround, switch, tergiversant, tergiversating,
   tergiversation, tergiversator, total change, traitor, transition,
   turn, turnaround, turncoat, turning, turntail, upheaval, variation,
   variety, violent change, volte-face, worsening