Avoiding injustice starts before conflict: speak truthfully, document entrusted property where useful, respect agreements and listen fairly before blaming anyone.
If someone discovers that they have wronged a person, merely feeling regret does not by itself return the harmed person's right. They should stop the wrongdoing and seek to restore the right as appropriate.
This develops the previous discussion of character: a clean heart must also appear in fair actions. A friendly appearance cannot excuse withholding someone's property or dignity.