Paid a brief visit and asked for help (6,2)
I believe the answer is:
called in
'paid a brief visit' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Maybe you can see an association between them that I don't see?
'asked for help' is the wordplay.
'asked' becomes 'called' (calling is a kind of asking).
'for help' becomes 'in' (I can't justify this - if you can you should give a lot more credence to this answer).
'called'+'in'='CALLED IN'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for called in that I've seen before include "judge indicated one's to be summoned" , "Landed in court" .)