Oration rewritten for part of Canada (7)
I believe the answer is:
ontario
'part of canada' is the definition.
('Ontario' is part of 'canada')
'oration rewritten' is the wordplay.
'rewritten' indicates an anagram.
'oration' anagrammed gives 'ONTARIO'.
'for' acts as a link.
(Other definitions for ontario that I've seen before include "provincial area" , "city" , "Canadian province and Great Lake" , "Province of central Canada" , "one of the provinces" .)