No one likes to break a promise, but...

No one likes to break a promise, but sometimes it’s inevitable. You suddenly have a work emergency that takes priority over another project, or you encounter some unexpected roadblocks to completing an assignment. Or perhaps there is a family matter that takes precedence.

The question is: how do you do break the news preserving your reputation and the relationships?

1. Give advance notice. Do not break the news at the last minute. The minute it becomes obvious that you might have difficulty meeting your commitment you should give that person a heads up. No one likes receiving that news, but being told in advance means the other party can make contingency plans. It’s another matter entirely when you back out last minute.
2. Apologize personally. It's your promise that is being broken and you need to be the one to apologize. The other person will feel even more slighted if you have someone else do your apologizing for you.
3. Try to come up with other options. Before you break the news take as much time as you can spare coming up with possible alternative solutions. You will usually find you have some good ideas, but offering them after the other person is annoyed won't win you any points. It’s a lot less harsh to offer alternatives, rather than just shutting someone down with a cold, hard “no.”

What are some ways people broke the news to you about having to break their promise?  which ways were good and which ways were not?