You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am planning to book a ticket to attend a music event at PHX. Can you please help me out to book a ticket from IAH?

ASSISTANT: Sure, please share your trip dates.

USER: I am planning to travel on July 21 and return back on July 23.

ASSISTANT: Do you prefer a direct or connecting flight?

USER: I am looking for a direct flight.

ASSISTANT: In which class do you prefer to travel?

USER: I am ok with any class.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: May I know your name?

USER: My name is Frank Campbell.

ASSISTANT: Sorry Frank Campbell, no flights are available on your route.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you for contacting us.