Consequence of retiring Lawrence welcoming Clare to party (6)
I believe the answer is:
effect
'consequence' is the definition.
('effect' can be a synonym of 'consequence')
'retiring lawrence welcoming clare to party' is the wordplay.
'retiring' is a reversal indicator.
'lawrence' becomes 'te'.
'welcoming' is an insertion indicator (in sense of 'inviting in').
'clare' becomes 'ce' (I've seen this in other clues).
'to party' becomes 'ff' (I've seen this in other clues**).
'ce'+'ff'='ceff'
'te' enclosing 'ceff' is 'tceffe'.
'tceffe' reversed gives 'EFFECT'.
'of' acts as a link.
(Other definitions for effect that I've seen before include "See 7" , "It follows cause" , "Consequence, outcome" , "Change produced by action, result" , "Result; make happen" .)