Apologize quickly!
"We have educated him well since Liam was little. He had never made a fatal mistake like this. If he actually did that, we bet our son didn't mean to do that. Please forgive him just this time..."
"Sir, ma'am, with all due respect, I can't withdraw Liam's punishment," the principal straightened his back. "This is school. So if he's wrong, then he's wrong. If I withdrew Liam's sentence, many students would have done the same thing as Liam and hoped I would withdraw their sentence too,"
"Please stand and discuss this carefully," the principal said.
"Sir, the one who was wrong was me and my husband, not Liam!" The woman shook her head. "We should have educated Liam a little more. Please give our child a chance and don't bring this matter to the education office,"
"If you tell this to the education office, what will be the future of our child..."