Idiom
in behalf of someone and in someone's behalf; on behalf of sb on sb's behalf; in sb's name
Theme: SUBSTITUTION
[doing something] as someone's agent; [doing something] in place of someone; for the benefit of someone.I'm writing in behalf of Mr. Smith, who has applied for a job with your company.I'm calling on behalf of my client, who wishes to complain about your actions.I'm calling in her behalfI'm acting on your behalf