Trend in retirement is correct (4)
I believe the answer is:
edit
'is correct' is the definition.
(edit can mean to correct or emend)
'trend in retirement' is the wordplay.
'trend' becomes 'tide' (I've seen this in another clue).
'in retirement' says the letters should be written backwards (retire can mean to go back or backwards).
'tide' reversed gives 'EDIT'.
(Other definitions for edit that I've seen before include "Supervise the publication of" , "Amend and correct" , "amend copy" , "Fix" , "Rewrite" .)