Reject change, unhappy (4,4)

I believe the answer is:

turn down

'reject' is the definition.
(synonyms)

'change unhappy' is the wordplay.
'change' becomes 'turn' (turning is a kind of changing).
'unhappy' becomes 'down' (I've seen this before).
'turn'+'down'='TURN-DOWN'

(Other definitions for turn down that I've seen before include "Lower volume" , "Reject - reduce volume" , "Spurn" , "mark the place" , "Dim - reject" .)

I've seen this clue in The Telegraph.

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