Musical work: Farewell to Prison? (7)
I believe the answer is:
cantata
'musical work' is the definition.
(I've seen this before)
'farewell to prison?' is the wordplay.
'farewell' becomes 'tata' (I have seen 'A Farewell' mean 'ta-ta' so perhaps 'farewell' could also mean 'ta-ta').
'to' says to put letters next to each other (I've seen this in other clues).
'prison?' becomes 'can' (the can is American slang for prison).
'tata' after 'can' is 'CANTATA'.
(Other definitions for cantata that I've seen before include "(a musical work)" , "aria" , "Short oratorio performed in concert" , "Sacred choral piece" , "Musical piece" .)