Make a short visit with John and relations (4,2)
I believe the answer is:
look in
'make a short visit' is the definition.
(I've seen this before)
'john and relations' is the wordplay.
'john' becomes 'loo' (loo is a kind of john).
'and' says to put letters next to each other.
'relations' becomes 'kin' (I've seen this before).
'loo'+'kin'='LOOK-IN'
'with' is the link.
(Other definitions for look in that I've seen before include "Make a short visit" , "Chance to participate" .)