What happens at noon? Changes! (6)
I believe the answer is:
amends
'changes' is the definition.
(to amend something is to change it for the better)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for amends that I've seen before include "Make these to atone for injuries or loss caused" , "Makes minor improvements" , "Alters and improves" , "Atonement" , "Make these to make up for past wrongs" .)