Ancient local arranged annulment (12)
I believe the answer is:
cancellation
'annulment' is the definition.
(I've seen this before)
'ancient local arranged' is the wordplay.
'arranged' is an anagram indicator (letters rearranged).
'ancient'+'local'='ancientlocal'
'ancientlocal' anagrammed gives 'CANCELLATION'.
(Other definitions for cancellation that I've seen before include "Abandonment" , "Annulment" , "shelving" , "Repeal" .)