Correct reversal of flow (4)
I believe the answer is:
edit
'correct' is the definition.
(thesaurus)
'reversal of flow' is the wordplay.
'reversal of' says the letters should be written in reverse.
'flow' becomes 'tide' (tiding is a kind of flowing).
'tide' in reverse letter order is 'EDIT'.
(Other definitions for edit that I've seen before include "Prepare text for publication" , "Amend a publication" , "Amend and correct" , "Prepare (material) for publication" , "Rework (text)" .)