Write a short note with a request. (Написать короткою записку с просьбой).
  Вот идея:
you lost your mobile phone today and you need one tonight. ( Вы потеряли свой мобильный телефон, а вам он нужен сегодня).
 Заранее спасибо!

Hi (name)!Could you do me a favor tonight? Yesterday I've lost my phone and I'm afraid I can't find it anywhere. At 10 pm I am gonna go to the club with my friends and I need to keep in touch with them. So I wonder if you would mind helping me by lending me your cellphone? I will really appreciate the help you can offer me and will be happy to return the favor when the opportunity arises.                                                                                  Eternally yours, (name)