What is the way to atone for sins committed against deceased relatives, to seek forgiveness from Allah, and to avoid accountability on the Day of Judgment?

Whoever transgresses against a Muslim's honor or harms them must seek their forgiveness in this life. If the wronged person dies before this happens, the oppressor is in danger and must increase their good deeds so that the wronged person may be compensated from them. Some scholars have stated that they should seek forgiveness and supplicate for the wronged person. If they slandered them in front of people, they should praise them and commend them in front of the same people for their good qualities.