So you know how a polite request may be phrased as a question, eg. "May I have seconds?". And how an appropriate answer for such a question may be a simple request, indicating the answerer's desire for the inquirer to be at ease, eg. "please do."?

So today my non-native ass had the following exchange:
her: "I'd love to keep you company but I have to call a friend who asked me dearly to call him back when I get home."
me: "please leave"