Deal with composer in audition (6)
I believe the answer is:
handle
'deal with' is the definition.
(synonyms)
'composer in audition' is the wordplay.
'composer' becomes 'handel' (George Frideric Handel).
'in audition' shows a homophone (sound like) (audition can mean hearing).
'handel' sounds like 'HANDLE'.
(Other definitions for handle that I've seen before include "Touch, hold, move" , "Informally, personal title or name - sounds manual" , "Manage - touch - hilt" , "Trade in" , "Part by which something is carried" .)