behalf

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

(noun) for someone's benefit (usually expressed as `in behalf' rather than `on behalf' and usually with a possessive). Examples: "In your behalf." "Campaigning in his own behalf." "Spoke a good word in his friend's behalf."