An emissary is a representative
An emissary is someone who is sent as a official representative to another party. It is often in political spheres about an envoy, if an important one is not able to pass somewhere, an envoy is sent, or if double agreements are made, an envoy is sent. Often the emissary has the same powers as the original person, but sometimes it is more of an obligation of attendance and the emissary has no rights or authority.