Passed on a message concerning new delay (7)
I believe the answer is:
relayed
'passed' is the definition.
(relaying is a kind of passing)
'message concerning new delay' is the wordplay.
I cannot quite see how this works, but
'concerning' could be 're' (both can mean on a particular topic) and 're' is found in the answer.
an anagram of 'delay' is 'layed' which is within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'on a' acts as a link.
Can you help me to learn more?
(Other definitions for relayed that I've seen before include "Layered (anag.)" , "Broadcast; passed on" , "Received and passed on" , "Passed along" , "Transmitted along" .)