You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how best can I assist you today?

USER: Can you please help me to book a flight from LAX to DCA?

ASSISTANT: Do you need a connecting flight?

USER: Yes, I need a connecting flight.

ASSISTANT: On which dates do you want to travel?

USER: I want to travel on May 21 and intend to return on May 23.

ASSISTANT: Do you need another specifications?

USER: I prefer to travel in an normal-cost airline.

ASSISTANT: Can I know your good name?

USER: Sure, my name is Mary King.

ASSISTANT: Thank you for your good name, there are no flights found with the given information.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you.