You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Please help me to book a flight ticket from IAD to DCA.

ASSISTANT: Sure, can you please share me your travelling dates?

USER: My journey dates are from Sept, 05 to Sept, 07.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: Is there any other specifications?

USER: I prefer normal-cost airlines.

ASSISTANT: May I know your name?

USER: Helen Evans.

ASSISTANT: Sorry, there were no flights with your given details.

USER: Thank you for your information.

ASSISTANT: Thank you for reaching us.