You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Please help me to book a flight ticket from DFW to PHX.

ASSISTANT: Sure, may I know your travelling dates?

USER: My trip dates are from Feb, 18 to Feb, 20.

ASSISTANT: Could you share your connection limit?

USER: I need a single connecting flight.

ASSISTANT: Do you have any other preferences?

USER: I prefer an economy class.

ASSISTANT: Ok, wait a minute.

USER: Ok.

ASSISTANT: Sorry, there are no flights available.

USER: Thanks for your information.

ASSISTANT: May I Know your name?

USER: My name is Ryan Robinson.

ASSISTANT: Thank you for choosing us.