You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to book a ticket from IAD to EWR. Can you please help me out?

ASSISTANT: Yes, can you share me your dates of travel?

USER: I am planning to travel on Oct 17 and return back on Oct 19.

ASSISTANT: Do you have any preferences?

USER: My return time is evening.

ASSISTANT: Do you have any connection limit?

USER: I am looking for a connecting flight.

ASSISTANT: Can I know your name?

USER: My name is Katherine Robert.

ASSISTANT: Sorry to inform you that there are no flights found on your requested criteria.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for reaching us.