보고 — To, Indirect object marker

This expression is used to indicate the person to whom a question, request, suggestion or order is verbally directed. It is mainly used in colloquial speech when emoting the speech of others.

Details

1. This expression can be replaced with 더러 with no major change in meaning.

희선 씨가 세훈 씨더러 보고서 쓰는 걸 도와 달라고 하던데요.

의사 선생님이 아버지더러 담배를 끊으라고 하시더라고요.

In addition, when 더러 is used after the pronoun 나 or 너, they are often combined with ㄹ더러 instead of simply 더러.

세호가 날더러 동아리 활동을 같이 하자고 하네.

누가 널더러 이 일을 하라고 했어?

2. The particles 보고 and 더러 can be replaced with both 한테 and 에게.

김 선생님이 저보고 말을 놓으라고 하셨어요.

However, when the sentence is not expressing quoted speech, then 한테 and 에게 cannot be replaced with 보고 or 더러.

요즘 수현 씨보고 무슨 일 있나요? ✕

Using 보고 here is incorrect because the sentence is not expressing quoted speech.