Ring again to cancel (6)
I believe the answer is:
repeal
I believe this is a double definition.
'ring again' is the first definition.
('peal' can be a synonym for 'ring' so perhaps 'repeal' is OK for 'ring again')
'to cancel' is the second definition.
(I know that repeal is a more specific form of the action cancel)
(Other definitions for repeal that I've seen before include "Annulment" , "'Annul, revoke (6)'" , "Abrogate" , "Annul an act of parliament" , "Withdraw law officially" .)