Pay a brief visit and ask for help (4,2)
I believe the answer is:
call in
'ask for help' is the definition.
(I've seen this in another clue)
'pay a brief visit and' is the wordplay.
'pay a brief visit' becomes 'calli' (I can't explain this - if you can you should believe this answer much more).
'and' becomes 'n' (common abbreviation for 'and').
'calli'+'n'='CALL IN'
Can you help me to learn more?
(Other definitions for call in that I've seen before include "Drop by" , "Visit" .)