It’s legal, due, to change President (2,6)
I believe the answer is:
de gaulle
'president' is the definition.
(Charles de Gaulle)
'it's legal due to change' is the wordplay.
'to change' indicates an anagram.
'legal'+'due'='legaldue'
'legaldue' is an anagram of 'DE GAULLE'.
(Other definitions for de gaulle that I've seen before include "Former French president" , "General .. ...... was French post-war leader" , "Gen. -, French leader" , "Free French leader" , "Old statesman" .)