You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: Please help me to book a flight ticket from EWR to SEA.

ASSISTANT: Sure, on what dates will you be travelling?

USER: My travelling dates are from Mar, 20 to Mar, 22.

ASSISTANT: Do you prefer an economy class or business class?

USER: I prefer an economy class.

ASSISTANT: How many connections do you need?

USER: I need a single connecting flight.

ASSISTANT: Is there any other requirements?

USER: I need to return in the morning and I prefer normal-cost airlines.

ASSISTANT: May I  know your name?

USER: I am Kevin Martinez.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Kevin Martinez, we regret to inform you that there are no flights available matching your credentials.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for approaching us.