You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you?

USER: I want to book a ticket from Las Vegas to Oakland.

ASSISTANT: Sure, let me know your travel dates please?

USER: Travel dates are Dec, 16 and Dec, 18.

ASSISTANT: May I know your connection limit?

USER: I prefer connecting flight.

ASSISTANT: Ok, is there any class preference?

USER: I would like to prefer economy class.

ASSISTANT: Do you have any time concern?

USER: I am comfortable to travel any time.

ASSISTANT: Do you need any airline preference?

USER: I prefer to fly in a normal-cost airline.

ASSISTANT: Can I know your name please?

USER: My name is Steven Walker.

ASSISTANT: Sorry to inform you that there are no flight services available on your given requirements.

USER: Thank you.

ASSISTANT: Thanks for contacting us.