Atoning means undoing and correcting errors. When an individual can truly forgive, they essentially atone. The miracle that ensues is the personalized experience of revelation (experience of higher love). This is the feeling of being at- one (atone) with the source of such love.
Many Christians believe that atonement is essentially the work of God, who, in the Nazarene, reconciles mankind to Himself. Atonement is not a sacrifice of an individual to appease their God. This would infer that the Great Spirit is cruel and heartless.