Letter Of Intent To Vacate How Do I Start A Letter Of Intent?

How do I start a letter of intent? - letter of intent to vacate

I still have a letter of intent, the will of my sister, transfer to another university and another course to demonstrate. I have put the ideas of what to in the letter, but do not know what kind of sentence, to use an introduction. Can you examples? Thank you in advance.

PS - I have a deal with my sister, which is why she would write your letter.