This structure is used to politely ask somebody to convey a message.
It can be used for direct speech.
•ワンさんに「後で電話をください」と伝えていただけますか。
Could you please ask Mr Wang to call me later?
And and with the plain from for indirect speech.
田中さんに明日行けないと伝えていただけませんか。
Could you please tell Mr Tanaka that I won’t be able to go tomorrow?