Messenger, envoy (6)
I believe the answer is:
herald
This clue is a double definition.
'messenger' is the first definition.
(I know that herald is a type of messenger)
'envoy' is the second definition.
(thesaurus)
(Other definitions for herald that I've seen before include "Ceremonial messenger" , "Presage for old announcer" , "Harbinger, precursor" , "Person who announces important news" , "Signal the arrival of" .)