substitute; proxy; representative; agent
Refers to a person who appears, acts, or handles a matter in place of someone else. Often overlaps with 代理人, which is the more explicit term for a legally or formally authorized agent.
If the person cannot attend, they may appoint a proxy.
He attended the meeting as the president's representative.
Since my father was hospitalized, we had my brother act as his proxy to proceed with the paperwork.
I attended the meeting as the president's proxy.
代表者 means a representative chosen to speak for a group or organization, while 代人 usually means someone substituting for one particular individual.
counter for people
A Sino-Japanese compound conventionally combining 代, 'substitution' or 'acting in place of,' with 人, 'person.'