Change people notice, all round (5)
I believe the answer is:
amend
'change' is the definition.
(amending is a kind of changing)
'people notice all round' is the wordplay.
'people' becomes 'men' (man is a kind of person).
'notice' becomes 'ad'.
'all round' means one lot of letters goes inside another.
'men' placed into 'ad' is 'AMEND'.
(Other definitions for amend that I've seen before include "Alter in detail" , "Modify - edit" , "Rectify" , "Make small changes to" , "Put right" .)