Answer:
Break a Promise:
I had to break a promise when my two mutual friends were fighting with each other over their car damage. Each one was thinking that other had damaged intentionally. I had to break a promise that It was due to an accident and nothing was done intentionally but the other has promised me not to tell you before he repairs the car. I had to break the promise with my one of friends to end up their fight.
Tell a Lie:
I never tell a lie and always believe in speaking truth. There was a situation where I had to tell a lie to my cousin who was in hospital and doctors informed me that he is at last stage of cancer and there are very few chances for his survival. I lied him saying that he is at initial stage and proper treatment can free him from this deadly disease to keep him motivated to live.
Explanation:
Telling a lie or breaking a promise is only acceptable in utilitarian ethics, where there is good for everyone. A person can lie to someone if he believes that speaking truth may create problems.