To, The Principal, [School Name], [City]
Date: [Date]
Subject: Application for half-day leave
Respected Sir/Madam,
I am a student of Class [Class], Section [Section]. I have a [reason, e.g. doctor's appointment] today at [time], and I therefore request permission to leave school after the [e.g. fourth] period.
My [parent/guardian] will pick me up from the school gate. Kindly grant me half-day leave.
Thank you.
Yours obediently, [Your Name] Class [Class], Roll No. [Roll Number]