behalf

as the agent of or on someone's part (usually expressed as "on behalf of" rather than "in behalf of"); "the guardian signed the contract on behalf of the minor child"; "this letter is written on behalf of my client";

for someone's benefit (usually expressed as `in behalf' rather than `on behalf' and usually with a possessive); "in your behalf"; "campaigning in his own behalf"; "spoke a good word in his friend's behalf"