To:XXX,Manager
I would like to know if I could ask for a casual leave of absence for one day on 时间,this Friday.I have a bad headache and I want to go hospital.Because I have done most of my work ,this week is not as busy as the other weekdays,I think a one-day leave this Friday may be the best solution.I apologize for the inconvenience my absence from work may cause.Thanks.I will call you Or you can call me at any time.