Management a Critical incident High performer but late for work

You're in you are an elementary school principal. one of your best teachers perhaps the best is causing a bit of uproar. she is in her second year on staff after graduation from college and is doing a wonderful job with second graders. They're happy the parents are happy you happy. The other teachers aren't happy at least some of them aren't. Two of the more outspoken and Senior teachers come to you today with a request. Do something about her they said. she is constantly late in the morning. So, you know the policy is for the teachers to be in the classroom at least 30 minutes before school starts. you are aware of tardiness, but you also know that she constantly stays late in if most stay late in if most often the last teacher out of the building at the end of the day. she isn't aware that her co-worker has complained about her you can't put this off because the grumbling is starting to spread.

Questions what do you do when why? how can you turn this into an opportunity to develop in an approach that accommodates a range of personal work Styles and different classroom approaches oh well holding up high-performance standards?