You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Angela Hall.

ASSISTANT: How may I assist you today?

USER: Can you make a reservation for me from DEN to DCA, to meet my family.

ASSISTANT: May I know your trip dates?

USER: Sure, my trip dates are 07/18 and 07/20.

ASSISTANT: There is no flights for this routes.

USER: It's ok, thanks for your information.

ASSISTANT: Welcome.