Cancel, rescind (6)
I believe the answer is:
revoke
This clue is a double definition.
'cancel' is the first definition.
(I know that revoke has the is a more specific form of the action cancel)
'rescind' is the second definition.
(I know that rescind can be written as revoke)
(Other definitions for revoke that I've seen before include "Annul by recalling" , "Annul (a decree/decision)" , "(In card games) fail to follow suit" , "Officially cancel a decree" , "'Officially cancel, a licence say (6)'" .)