Remember this 4A's:
1. Acknowledge - Acknowledge that the other person is hurting. They're feelings are valid.
2. Accept - Accept the responsibility. Own that you made a mistake.
3. Amend - Make amends/Make a plan so you won't do the same mistake all over again.
4. Assure - Don't only make a promise that you won't do it again but also change your action. If you didn't change your actions, you're not sorry at all.