You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: Helen Nelson here. I want to book a flight ticket from DFW to IAD. Can you please help me in that?

ASSISTANT: Sure. Can you please mention your preferable travel dates?

USER: My trip dates are Feb 03 to Feb 05.

ASSISTANT: Are you ok with connecting flight or you need a direct flight?

USER: I need a connecting flight.

ASSISTANT: Do you need any specific depart and arrival time for this trip?

USER: My return should be in the evening.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: Ok, no problem. I will choose alternate way to reach my destination. Thank you for giving information.

ASSISTANT: Thank you for reaching us.