Delegation - Sign a document on behalf of with the signature of the original recipient

Hi all,

I'm looking into a solution for a specific case a client is requesting. This client wants the assistant to be able to sign on behalf of the director. When the director delegates the document to be signed by the assistant, the assitant can sign it but it will be signed in the name of the assistant.

My client wants the assistant to be able to sign, but with the signature and the name of the director displayed and not that of the assistant. 

Is there a solution to this problem or another way that would be better? Or is this simply not possible?

Thank you!