Put right about costume (7)
I believe the answer is:
redress
'put right' is the definition.
(I've seen this before)
'about costume' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'costume' becomes 'dress' (I've seen this in other clues).
're'+'dress'='REDRESS'
(Other definitions for redress that I've seen before include "Make amends for" , "Get back into gear" , "Put right" , "set things right" , "relief" .)