Jazz tune is up for associates (6)
I believe the answer is:
unites
'associates' is the definition.
(both can mean to join or put together)
'jazz tune is up' is the wordplay.
'tune is' anagrams to 'UNITES'.
Though, I'm not sure how the anagram is indicated.
'for' is the link.
(Other definitions for unites that I've seen before include "Joins together as one" , "Becomes one" , "Marries" , "Comes together as one" , "Merges" .)