"Asking for permission to do something takes many different forms. Perhaps you need to get permission to do something at work, or perhaps you need to ask a friend for permission to use one of her possessions, or maybe you need to ask the teacher if you can leave room the for a moment or two. Remember to use polite forms when asking for permission to do something or use an object as you are asking a favor of that person."

Read more at Asking for, Granting and Refusing Permission in English by  Kenneth Beare