You : Where's John?
Friend : Isn't he in the office?
You : I didn't see him there. If you see him please tell him to drop me a line. Thank you.
You : Have you seen John today?
Friend : No. I havn't.
You : If you see him could you tell him to call Peter?
Friend : Sure.
You : Is John around?
Friend : He might be in the pantry.
You : Can you tell him that the boss wants to see him as soon as poosible?