You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Karen white, want to travel from DCA to IAH. Please help me in booking my ticket.

ASSISTANT: May I know your trip dates?

USER: Sure, my trip dates are from 11/05 to 11/07.

ASSISTANT: There is no flights available.

USER: It's ok, thank you.

ASSISTANT: Most welcome.