You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Could you please book me a flight ticket from PHX to IAD?

ASSISTANT: Sure, please share your journey dates?

USER: I will leave on Mar 19th and return on Mar 21st.

ASSISTANT: Do you have any specifications?

USER: I need 1 flag stop in the middle.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: May I know your good name?

USER: I am John Hernandez.

ASSISTANT: Sorry, no flights found on your given details.

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you for choosing us.