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' is a reversal indicator.
'and' means one lot of letters go next to another.
'ring' becomes 'peal' (pealing is a kind of ringing).
'pa' in reverse letter order is 'ap'.
'ap'+'peal'='APPEAL'
'to' is the 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" .)