Withdrawn complaint about a single (4,3)
I believe the answer is:
gone out
'withdrawn' is the definition.
The definition and answer can be both related to change as well as being past participle verbs.
Maybe there's a link between them I don't understand?
'complaint about a single' is the wordplay.
'complaint' becomes 'gout' (gout is a kind of health problem).
'about' indicates putting letters inside.
'a single' becomes 'one' (a single thing - only one).
'gout' enclosing 'one' is 'GONE OUT'.
Can you help me to learn more?
(Other definitions for gone out that I've seen before include "On The Town possibly" , "dated" , "Having left the house (to go to a party?)" .)