Ruth is an international student pursuing her master's degree at a university in Vancouver. Upon starting her third semester, she got a part-time job as a warehouse associate at Nova Unlimited. It has been a dream working for this company and it is known to be the #1 online retailer in Canada. The company provides its employees with attractive health and personal benefits and also pays well.
Additionally, the employees are friendly and are supportive of Ruth as she works part- time and studies full time. For these reasons, Ruth hopes to transition into a managerial role when she completes her studies and is permitted to work more than twenty hours.
It is Ruth's responsibility to share her school schedule with her supervisor, Tina, at least a month in advance so that she can consider any limitations while writing the schedule. However, Ruth forgo mention that she has exams at the end of the month in advance so that she can consider any limitations while writing the schedule.
However, Ruth forgot to mention that she has exams at the end of the month. A few days before her first exam, Ruth notices that she is scheduled for a shift that overlaps with her exam time. She cannot reschedule her exam and has to inform her boss that she is unable to work the shift.
Ruth has always struggled with time management and is afraid to tell her boss about this mistake. This is not the first time that she was unable to do a shift because of poor planning. The team is also short-staffed, and there isn't anyone else available to do the shift.

How should Ruth communicate this oversight to her boss? Write an outline of her message.