Subject: Application for Permit to Change Optional Subject
With due respect and humble submission to say that I am a student of (Which Class..) of your school. I took up (subject name) as my optional subject. But I am very week in this subject, I have to do extra effort for this subject. Because of poor subject knowledge, I am unable to study hard on (subject name). In the last examination I got only thirty per cent marks in it. I think that optional (subject name) will be better for me and for my future success.
Therefore, I pray and hope that you will be kind enough to permit me to change this subject and oblige thereby.
Your Obedient Student,