Canon with dire changes for sacrament (9)
I believe the answer is:
ordinance
'sacrament' is the definition.
(thesaurus)
'canon with dire changes' is the wordplay.
'with' means one lot of letters go next to another.
'changes' is an anagram indicator.
'canon'+'dire'='canondire'
'canondire' with letters rearranged gives 'ORDINANCE'.
'for' is the link.
(Other definitions for ordinance that I've seen before include "Command" , "practice" , "law" , "Showing resolution" , "Bill" .)