Try present with one label round (4,2,1,2)
I believe the answer is:
give it a go
'try' is the definition.
(I've seen this before)
'present with one label round' is the wordplay.
'present with' becomes 'give'.
'one' becomes 'i' (Roman numeral).
'label' becomes 'tag' ('tag' can be a synonym of 'label').
'round' becomes 'o' (round can mean a round object**).
'give'+'i'+'tag'+'o'='GIVE IT A GO'
(Other definitions for give it a go that I've seen before include "Have a shot at, make an attempt" , "Try" , "Make an attempt at something" .)