Modify so that a girl will get the point (5)
I believe the answer is:
adapt
'modify' is the definition.
(to modify is to improve or adapt)
'that a girl will get the point' is the wordplay.
'that a girl' becomes 'ada' (girl's name).
'will get' means one lot of letters go next to another.
'the point' becomes 'pt' (abbreviation for point).
'ada'+'pt'='ADAPT'
'so' is the link.
(Other definitions for adapt that I've seen before include "Adjust to changed circumstances" , "Change to fit new circumstances" , "rewrite for broadcasting" , "match" , "Alter, amend" .)