Having knocked off Charlie, now make amends (5)

I believe the answer is:

atone

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'make amends' is the definition.
(to atone is to make amends for a wrong deed)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for atone that I've seen before include "Recompense" , "Pay the price" , "Make redress" , "Turn away from sin and do penance" , "Make amends, being at one" .)

I've seen this clue in The Sunday Times and The Times.

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