You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my travelling dates are from 08/12 to 08/14.

ASSISTANT: Sorry, there is no flights available.

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

ASSISTANT: Most welcome.