Noon? Correct! (5)
I believe the answer is:
amend
'correct' is the definition.
(amending is a kind of correcting)
I don't understand how the remainder of the clue works.
(Other definitions for amend that I've seen before include "Change for the better" , "Put right" , "Correct or alter to improve" , "Make small changes to" , "Make minor improvements to (a document)" .)