You need not worry when it comes to writing a letter to change a course, all you need to ensure is that you have a valid reason for wanting to leave the course that you are on and why you should be accepted onto the new course with the new subject. As long as you keep the language formal and don't use anything that is going to seem too friendly, then you are not going to be turned down for the course change and you are going to have the outcome that you want. Writing a letter to change a course is something that you should take seriously, but it is not going to mean the matter of life and death, if the first one doesn't sound right, then simply write it again from a different angle and see what difference that makes to the letter as a whole.
You will need to ensure that you address the person in the letter as sir or madam as this is going to ensure that you are going to be taken seriously and that they are instantly going to be impressed with the letter that you have written as you have written it with respect and know that the matter is very important. The key is to write the letter the complete opposite as to how you would simply write it to a friend. You want to appear professional and adult about the situation - which you are obviously not going to do if you were to be writing to a friend.
There are many different sample letters that you are going to be able to find when you do a search online and this is going to ensure that you can see how it should be set out and that you are not going to make any errors which could have been avoided.
You will need to ensure that you address the person in the letter as sir or madam as this is going to ensure that you are going to be taken seriously and that they are instantly going to be impressed with the letter that you have written as you have written it with respect and know that the matter is very important. The key is to write the letter the complete opposite as to how you would simply write it to a friend. You want to appear professional and adult about the situation - which you are obviously not going to do if you were to be writing to a friend.
There are many different sample letters that you are going to be able to find when you do a search online and this is going to ensure that you can see how it should be set out and that you are not going to make any errors which could have been avoided.