Developing late, helping to change (10)
I believe the answer is:
alteration
'change' is the definition.
('alteration' can be a synonym of 'change')
'developing late helping' is the wordplay.
'developing' indicates an anagram.
'helping' becomes 'ration' (I've seen this before).
'late' anagrammed gives 'alte'.
'alte'+'ration'='ALTERATION'
'to' acts as a link.
(Other definitions for alteration that I've seen before include "Adjustment" , "Amendment" , "Change" .)