Pop back and ring to make a request (6)
I believe the answer is:
appeal
'make a request' is the definition.
(appealing is a kind of making a request)
'pop back and ring' is the wordplay.
'pop' becomes 'pa' (both can mean father).
'back' says the letters should be written in reverse.
'and' is a charade indicator (letters next to each other).
'ring' becomes 'peal' (synonyms).
'pa' reversed gives 'ap'.
'ap'+'peal'='APPEAL'
'to' acts as a link.
(Other definitions for appeal that I've seen before include "Earnest or urgent request" , "Supplication to take a higher court" , "Contest a verdict" , "Refer sentence to higher court for review" , "prayer" .)