The custom is to say Tefillas (prayer) Zakah before Kol Nidrei on the eve of Yom Kippur.

Part of it states as follows. “Since I know that there is hardly a righteous person in the world who never sins between man and his neighbor … therefore my heart aches within me, because for a sin between man and his neighbor, Yom Kippur does not atone until one appeases his neighbor … even the day of death does not atone … have mercy on me and allow me to find favor … in Your eyes and in the eyes of all people.

“…I extend complete forgiveness to everyone who has sinned against me, whether … or whether … and may no person be punished on my account. And just as I forgive everyone so may You grant me favor in every person’s eyes, so that he will grant me complete forgiveness.”

Tefillas Zakah is, so to speak, the last court of appeal when one doesn’t really know of anything that he might have done to someone else. But who knows? One may have said something and meant one thing but the other may have understood it in a different light and felt hurt. Or one may not be cognizant at all that he did or said something. However, for things that are open such as an argument, or an insult, etc. one needs to go to the other party and state his remorse and ask for forgiveness preferably as soon as possible after the incident, but certainly before Yom Kippur. Embarrassing? Quite likely. But think of it this way. If the other party were your boss and could fire you or hold back your raise, you would make amends, embarrassing or not. Here, it’s even more important.

¹ If one didn’t have a chance to say it before he can say it later, the sooner the better.