Resigns in stages, unhappy (5,4)

I believe the answer is:

steps down

'resigns' is the definition.
(step down from a job)

'stages unhappy' is the wordplay.
'stages' becomes 'steps' (both can mean parts of a process).
'unhappy' becomes 'down' (down can mean sad).
'steps'+'down'='STEPS DOWN'

'in' is the link.

I've seen this clue in The Times.

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