Correct people to appear in the commercial
I believe the answer is:
amend
'correct' is the definition.
(amending is a kind of correcting)
'people to appear in the commercial' is the wordplay.
'people' becomes 'men' (men are people).
'to appear in' is an insertion indicator.
'the commercial' becomes 'ad' (abbreviation for advertisement).
'men' put into 'ad' is 'AMEND'.
(Other definitions for amend that I've seen before include "Change, alter" , "Change to improve" , "Rectify" , "Modify - edit" , "Revise" .)