I just recently got a job as a research assistant over the holiday (which will later turn into an unpaid independent study project). Before hiring me for the job, my supervisor asked me if I would be taking a week off for vacation during the holidays. I told him no. However, for Christmas, I recieved (as a gift) tickets for an afternoon weekday show of an expensive stage production. The show is about an hour and a half from where I live so I would need to take most of the day off.I I will be informing my supervisor via email about this. How do I inform him/phrase the email?