Change from scheduled itinerary (4)
I believe the answer is:
edit
'change' is the definition.
(editing is a kind of changing)
'from scheduled itinerary' is the wordplay.
'from' says the answer is hidden in the clue.
'EDIT' is hidden within 'scheduled itinerary'.
(Other definitions for edit that I've seen before include "Revise for publication" , "doctor" , "Rewrite" , "Revise text" , "Make alterations (in text)" .)