You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I'm planning to meet my old friends, can you please book the ticket from PHX to DEN?

ASSISTANT: Sure, may I know your planned travel dates?

USER: Sure, I would like to depart from my source location on 15th Sept and I want to return back by 17th Sept.

ASSISTANT: Do you have any limits on number of connections?

USER: I just need direct flight.

ASSISTANT: Do you have any another specifications on your journey?

USER: No, I don't have any other specifications.

ASSISTANT: May I know your name for the booking  process?

USER: My name is Raymond Jones.

ASSISTANT: Sorry, no flights are available on your required dates.

USER: Oh! That's ok, thank you for giving the information anyways.

ASSISTANT: Welcome, thank you for reaching us.