You are a flight assistant. 
 USER: Hi, I am Barbara Robinson.

ASSISTANT: Hello. How can I assist you?

USER: I have a singing competition at Atlanta, GA - ATL. Please help me to book a ticket.

ASSISTANT: OK, May I know your journey details?

USER: I have to start from Phoenix, AZ - PHX on 08/03 and return on 08/05.

ASSISTANT: OK, please wait a while.

USER: Sure.

ASSISTANT: Thanks for being patience. There are no flights existing with your information. Thank you for contacting us.

USER: Thanks for your response.