You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am planning a trip to Washington city, can you please book me a ticket from HOU to DCA?

ASSISTANT: On which date you like to travel?

USER: My preferable journey dates are from 10/08 to 10/10.

ASSISTANT: May I know  your name pleas?

USER: My name is Charles Robinson.

ASSISTANT: I am sorry no flights found on your dates.

USER: Ok, not an issue. I will find any alternate for this trip. Thank you for providing information.

ASSISTANT: Thank you for choosing us.