On review, sign it, ideally retaining process of redaction (7)
I believe the answer is:
editing
'process of redaction' is the definition.
'on review sign it ideally retaining' is the wordplay.
'on review' shows that the letters should be reversed in order.
'retaining' indicates a hidden word.
'gnitide' is hidden within 'sign it ideally'.
'gnitide' reversed gives 'EDITING'.
(Other definitions for editing that I've seen before include "Changing" , "Revising for publication" , "revision" , "Preparing for publication by correcting etc." , "Preparing (text) for publication" .)