Supersede (8)
'supersede' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for override that I've seen before include "Cancel by higher authority" , "Use one's authority to reject or cancel a decision" , "Counteract the normal operation" , "Disregard" , "Set aside by superior authority" .)
'supersede' is the definition.
(I know that supersede can be written as replace)
This is all the clue.
(Other definitions for replace that I've seen before include "Substitute, supplant" , "succeed" , "Put back in original position" , "Substitute, supersede" , "Provide a substitute for" .)