Hello Candidate,

You can write in that way: Keep in mind, when you submit this application check that the format.

Format should be correct or not any grammatical mistake.

I am writing this letter to request you for change of course. I had opted for ___________ (course name) for ___________ (course details), but due to ____________ (reason to change course) I want to change course to ___________ (new course). I request you to please allow me to change my course at the earliest.

Thankyou.