Well, if you want to take a certain course, you have to think a lot about it. Before writing a personal statement be sure that you know what you want to deal with. A personal statement is a very specific kind of writing. In it you describe why exactly you want to take a certain course. Once you decide to change a course, you will have to rewrite the personal statement.
So if you made up your mind that what you are currently studying doesn’t appeal to you, feel free to make a change! I think there is no need to tell you how to write a personal statement, you already know the procedure. In the rewritten personal statement you will have to write all the reasons that made you change your decision. Of course, it may seem quite strange for your professors that you decided to change a course, but things happen!
You should write about the skills and information you have already learned. You have to be grateful to your tutors who have shared their knowledge with you. But at the same time try to show how the acquired knowledge helped you reveal your real interests. Say that with everything you know you have discovered your true mission in this life. State the course that seems to be appealing and describe how it will help you bring all your ideas to life. You may also say that the current course won’t let you reveal all your potential.
Your task will be to persuade the appropriate body of your University that you have thought carefully and now you are ready to make the choice. No one wants you to study something completely not interesting. You are expected to show the best results! And that will be possible only if you will take the right course. After all, to err is human. No one will kill you or something for changing the course. The keys for success are to be persuasive and argumentative. You will do it! Good luck!