翻脸to suddenly turn hostile

• 他一变脸, 六亲不认。

  Once he gets angry, he completely forgets about everyone else.

【剧】the Chinese art of changing masks, in which the performer dons different masks in quick succession

现常喻指发生很大的变化to change

• 苏州工业园区海关干部管理体制从原来的任命制到竞争上岗的大“变脸”。

  The customs cadre management system at the Suzhou Industrial Park has changed from an appointment system to taking up jobs through competition.