Change commercial about workers (5)
I believe the answer is:
amend
'change' is the definition.
(amending is a kind of changing)
'commercial about workers' is the wordplay.
'commercial' becomes 'ad'.
'about' means one lot of letters goes inside another.
'workers' becomes 'men' (man is a kind of worker).
'ad' placed around 'men' is 'AMEND'.
(Other definitions for amend that I've seen before include "Put right" , "make an improvement" , "Rectify" , "Modify - edit" , "Make small improvements to" .)