Call on and see round, with one's relations (4,2)
I believe the answer is:
look in
'call on' is the definition.
(thesaurus)
'and see round with one's relations' is the wordplay.
I cannot quite see how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'see' could be 'look' (I've seen this in another clue) and 'look' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for look in that I've seen before include "Make a short visit" , "Chance to participate" .)