You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is David Clark.

ASSISTANT: How may I assist you?

USER: I want to travel for DFW for my brother's marriage.So, Will you please help me in booking my ticket from PHX to DFW?

ASSISTANT: Sure,may I know your travelling dates?

USER: Sure, my travelling dates are from 09/04 to 09/06.

ASSISTANT: Sorry to say that no flights found for your information.

USER: Oh! It's ok. Thank you.

ASSISTANT: Thank you, have a nice day.