You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please help me to book a ticket from PHX to IAD?

ASSISTANT: Sure, can you please share your travel dates?

USER: I want to start on May 1 and return on May 3.

ASSISTANT: Do you have any class preference?

USER: Yes, I would like to prefer business class.

ASSISTANT: May I know your connection limit?

USER: I need a connecting flight.

ASSISTANT: May I know your name to proceed further?

USER: David Jones here. I would prefer normal-cost airline.

ASSISTANT: Do you have any other requirement that you are looking for?

USER: I would prefer normal-cost airline.

ASSISTANT: David Jones, I am sorry to inform you that there is no flight available at your request.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for contacting us.