Section of choir on outing showing resolve (4,3)
I believe the answer is:
iron out
'resolve' is the definition.
(I've seen this before)
'section of choir on outing' is the wordplay.
'section of' indicates the answer is hidden within the clue.
'IRON OUT' is hidden within 'choir on outing'.
'showing' is the link.
(Other definitions for iron out that I've seen before include "Smooth, clear up" , "Settle a problem" , "Remove (a difficulty)" , "Settle, put right" , "Resolve" .)