Specifically, when daimyo or hatamoto (a direct retainer of the bakufu) were going to have an audience with seii taishogun (literally, "the great general who was to subdue the barbarians") or when a messenger taking a present from a daimyo was sent to the Edo castle, Sojaban checked the person's name and the content of the present to report them to the shogun, and, when the shogun gave a grant, notified the person of the message.
具体的には大名・旗本が征夷大将軍に拝謁する際、あるいは在国の大名が献上品を使者に持たせて江戸城に派遣した場合に、その氏名と献上品の内容を確認して将軍に報告し、将軍が下賜を行う際にその伝達にあたった。