Corporal returned with new mail to give out (8)
I believe the answer is:
proclaim
'give out' is the definition.
(give out can mean to proclaim or declare)
'corporal returned with new mail' is the wordplay.
'corporal' becomes 'corp' ().
'returned' says the letters should be written in reverse.
'with' is a charade indicator (letters next to each other).
'new' is an anagram indicator.
'corp' reversed gives 'proc'.
'mail' anagrammed gives 'laim'.
'proc'+'laim'='PROCLAIM'
'to' is the link.
(Other definitions for proclaim that I've seen before include "Broadcast" , "Make a public announcement" , "Reveal" , "Speak out" , "shout from the housetops" .)