Last week, in my column on “Measuring your customers’ satisfaction before you lose them,” I mentioned that when you fail to deliver on your promises, you need to sincerely apologize. Since then, I have received a number of comments from readers affirming the importance of an apology. Successful companies know that apologizing to a customer or employee when someone has made a mistake is the first step toward rebuilding that relationship.

By definition, an apology is a written or oral expression of remorse, sorrow or regret for having failed, injured or wronged another. It may involve asking for pardon or forgiveness. However, not everyone agrees on what an apology should contain — this may explain why apologies work in some situations and don’t work in others.

Gary Chapman and Jennifer Thomas wrote “The Five Languages of Apology” in 2006, revealing that people have different ways of apologizing, and what one person considers a sincere apology, another doesn’t. Many people don’t realize how critical apologies are for rebuilding relationships at work. Most organizations do not train employees on how to apologize, leaving people generally not very skilled in that area.

Why don’t people apologize more? They may not see themselves at fault. Other times, people are afraid that apologizing for not meeting a request will make them look weak in future dealings or negotiations. Yet research has shown that starting with an apology for failing to meet your commitments may be the best way to start a negotiation because it diffuses the potential bomb aimed in your direction. And many employees say having a leader who admits when he or she made a mistake is preferable to one who doesn’t admit when they are wrong.

Sometimes we don’t apologize because we are afraid the person will want more from us, when in fact they really just want someone to assume culpability. This helps them restore their own sense of justice and personal dignity.

What makes an effective apology?

Acknowledge what you are apologizing for. Just saying you’re sorry does not convey the same thing as saying why you are sorry.

Recognize that those behaviors caused the other person harm. Maybe it didn’t seem like a big deal to you that you were late in completing a project at work, but it may have caused your teammate stress or embarrassment in front of a client or boss.

Take responsibility for your actions. Even if you didn’t mean to yell at an employee, you have to assume responsibility for your actions. Recognize that what you did was a mistake and wrong.

Say “I’m sorry.” This is a good first step in reestablishing the relationships and rebuilding trust between parties.

Make restitution. Offer some ideas for how you can make things right again.

Show repentance. Pledge not to repeat the action (“I will try not to criticize you in public again”). And ask for forgiveness.

Be sincere. If not, it will be obvious to the other party and can damage the relationship even further.

It’s best to apologize in person. It shows the other party that you are serious. If that is not possible, sending a letter is more effective than e-mail. It’s also important to be timely. Don’t let weeks go by; otherwise the relationship can become more damaged and the issue can grow much larger.

If you are providing an apology in a letter, start your letter with the apology. Sometimes sending a handwritten letter is much more effective than a typed letter. It demonstrates that you took the time to really think about the issue.

Misunderstanding and conflicts at work are to be expected — people have different views, work styles and personalities. Don’t wait until the problem becomes so deep that your relationships with customers, peers or staff are ruined. And if someone sincerely apologizes to you, make sure you accept his or her apology if you want to rebuild the relationship.