Forgiveness, in a psychological sense, is the intentional and voluntary process by which one who may have felt initially wronged, victimized, harmed or hurt goes through a process in changing feelings.

Forgiveness involves willfully putting aside feelings of resentment toward someone who has committed a wrong, been unfair or hurtful, or otherwise harmed you in some way. Forgiveness is not merely accepting what happened or ceasing to be angry. Rather, it involves a voluntary transformation of your feelings, attitudes, and behavior, so that you are no longer dominated by resentment and can express compassion, generosity, or the like toward the person who wronged you.

Forgiveness is sometimes considered an important process in psychotherapy or counseling.

The REACH method teaches how to overcome lingering bad feelings toward someone who did you wrong.

https://www.health.harvard.edu/mind-and-mood/the-power-of-forgiveness