Journalist has soldiers improve (5)
I believe the answer is:
emend
'improve' is the definition.
(emending is a kind of improving)
'journalist has soldiers' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'has' is an insertion indicator.
'soldiers' becomes 'men' (I've seen this before).
'ed' going around 'men' is 'EMEND'.
(Other definitions for emend that I've seen before include "would appear better" , "Correct/revise (a text)" , "Alter to improve (text)" , "Rectify" , "Make correction in written material" .)