to act

• 出面干预

  step in

• 出面调解

  act as mediator

• 公开出面

  make an official appearance

• 由工会出面，组织这次体育比赛。

  This sports event was organized by the union.

• 他为什么不出面，而用你的名义?

  Why does he remain in the background, using your name?

• 他不愿出面。

  He is not willing to come forward.