and why.
The more unusual the request, the more convincing
the reason needs to be.The purpose of this form is to obtain information from the reader. If the reader is expecting the letter, the writer’s task is easy.
If the reader is not expecting your letter, then it is more difficult. In this case, following these four guidelines will be helpful:
State your purpose
List your questions or requested action
Offer something in return to encourage action
Follow up with a thank you note, e-mail, or phone call to the person who helped you with your request