You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Christopher Lewis, want to travel from DCA to EWR. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my travelling dates are from 09/16 to 09/18. Please check the flight with 1 connection.

ASSISTANT: Sorry, there is no flight available on these dates.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.