act (as substitute) for; act in place of
- 校長[社長]代理
- the acting principal [president]
- 彼は1週間先生の代理をつとめた
- He substituted for the teacher for a week.
- 大統領の入院中副大統領が代理をつとめた
- The Vice-President acted [stood in] for the President while he was in (the) hospital.
- 上司の代理で[として]会議に出席した
- I attended the conference in my boss's place./I represented my boss at the conference.
- 彼の代理で投票した
- I voted 「on his behalf [as his proxy].