Alma 39

Alma teaches his son, Corianton, some of the principles associated with repentance in that he should -

"...my son, I would that ye should repent and forsake your sins..." (Book of Mormon | Alma 39:9)

To truly repent, one must forsake that sin, turn from it, and never commit it again. And then -

"...turn to the Lord with all your mind, might, and strength; that ye lead away the hearts of no more to do wickedly; but rather return unto them, and acknowledge your faults and that wrong which ye have done." (Book of Mormon | Alma 39:13)

That is a difficult thing to do to return and acknowledge ones faults and wrongs committed, even when those of whom you have committed some form of sin to no consider it to be so. We see an example as the sons of Mosiah -

"...traveled throughout all the land of Zarahemla, and among all the people who were under the reign of king Mosiah, zealously striving to repair all the injuries which they had done to the church, confessing all their sins, and publishing all the things which they had seen, and explaining the prophecies and the scriptures to all who desired to hear them." (Book of Mormon | Mosiah 27:35)

This restitution is an essential component of repentance when it is possible. I personally believe the atonement extends to those that were sinned against.