Reformed persons finally make comeback (8)
I believe the answer is:
Here is my best explanation:
'comeback' is the definition.
'reformed persons finally make' is the subsidiary indication.
'reformed' indicates an anagram.
'finally' says to take the final letters.
The final letter of 'make' is 'e'.
'persons' is an anagram of 'respons'.
(Other definitions for response that I've seen before include "counter", "bid by partner", "Retort", "Reply, rejoinder", "See porn (anag) -- answer", "Press one for a reply", "Sees porn (anag) - answer", "'Answer, reply (8)'", "Answer - retort" and "Reaction, reply".)