____________ (School Name)
Subject: Permission for using lab
Most courteously, I am ________ (name) a student of your reputed school studying in _______ (class). My student ID number _______ (mention student ID number).
I am writing this letter in order to inform you that I am having a __________ (practical examination/project/exam/other) on __/__/____ (date) for ________ (subject) for which I want to practice the practical. Therefore, I am writing this letter to request your permission for allowing me to use the ________ (subject) lab for practice work.
I believe you would consider this as a genuine request and allow me to use the lab so that I will be able to revise the practicals.
____________ (roll number)