Dear Mr.Smith:
Since you are not here in the office,I'd like to leave this note for your permission.On Thursday,I am going to attend an important international conference,therefore,I want to ask for one day leave.But never mind,I will spend my spare time doing my work during the weekend.I wish that you will be generous enough to give me the permission.Thank you for your care.
Sincerely Yours,Wanghong