A: I've got to get up early tomorrow, so please give me a wake-up call. B: Of course. We can give you a call anytime you like. A: Actually, I need two calls, one at 7 and the other at 7:15. B: Your wish is our command. Expect a call at 7, and another one at 7:15. A: Wait a minute! I don't like 7:15, now that I think about it. Change it to 7:30. B: The second call is now changed to 7:30. Is there anything else we can help you with? A: Nothing that I can think of right now. If something comes up, though, I'll call you. B: We're here all night long if you need anything.