____________ (School Name),
Date: __/__/____ (Date)
Respected Sir/ Madam,
I write this letter in reference to ________ (name), a student of ________ (class) of your reputed school.
I write this letter in order to request you to kindly grant leave to my son/ daughter on date __/__/____ (mention date). I am requesting you to grant leave for the mentioned date, as he/ she is having an appointment with the dentist and for which ___________ (name of the student) needs to be present at the clinic on time.
I shall be highly obliged for your kind consideration.
___________ (roll number)