You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you?

USER: My name is Frank Lopez. Can you check whether any flights are available on dates 04/15 and 04/17?

ASSISTANT: Sure, may I please know your origin and destination airports?

USER: Sure, I would like to travel from PHX to ATL.

ASSISTANT: Ok, let me check.

USER: Ok.

ASSISTANT: Sorry to notify you that there is no flight available according to your criterion. Thanks for opting us.

USER: That's ok, thank you.