Revise pieces penned by journalist (5)
I believe the answer is:
emend
'revise' is the definition.
(I've seen this in another clue)
'pieces penned by journalist' is the wordplay.
'pieces' becomes 'men' (e.g. in chess).
'penned by' is an insertion indicator (inserted letters are penned in).
'journalist' becomes 'ed' (short for editor).
'men' placed inside 'ed' is 'EMEND'.
(Other definitions for emend that I've seen before include "Improve (writing)" , "Edit, improve" , "Remove faults from" , "Improve by altering" , "Correct; edit" .)