You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: Can you help me in booking from PHX to IAD?

ASSISTANT: Sure, can you please share your preferable journey dates?

USER: My trip dates are Dec 21 to Dec 23.

ASSISTANT: May I know your name please?

USER: I am William Lopez.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: No issue, thank you.

ASSISTANT: Thank you for reaching us.