on behalf
acting as someone's agent, acting for the benefit of someone
I was able to sign for the registered letter on my wife's behalf.

[TahlilGaran] English Idioms Dictionary ▲

on one's behalf
See: ON BEHALF OF.
{adv. phr.}, {informal}
1. For someone else; in your place.
My husband could not be here tonight, but I want to thank you on his behalf.

2. For the good of another person or group; as a help to someone.
My teacher went to the factory and spoke in my behalf when I was looking for a job.
Compare: IN BEHALF OF, ON ONE'S ACCOUNT.

[TahlilGaran] English Idioms Dictionary ▲

on someone's behalf
acting as someone's agent, acting for the benefit of someone
I was able to sign for the registered letter on my wife's behalf.

[TahlilGaran] English Idioms Dictionary ▲