Feedback is supporting an agent (7)
I believe the answer is:
replies
'feedback is supporting an agent' is the definition.
I can't judge whether this defines the answer.
'feedback is supporting an agent' is the wordplay.
'feedback' becomes 'lies' (I am not sure about this - if you are sure you should believe this answer much more).
'is supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'an agent' becomes 'rep' (short for representative).
'lies' after 'rep' is 'REPLIES'.
Can you help me to learn more?
(Other definitions for replies that I've seen before include "Reacts verbally" , "Responds" , "Answers" .)