You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Can you help me to book a flight ticket from DFW to DCA?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Please book for the dates May 4th and May 6th.

ASSISTANT: Do you have any preferences?

USER: Yes, I need a direct flight.

ASSISTANT: May I know your name please?

USER: My name is Sandra Gonzalez.

ASSISTANT: Sorry, there is no flight available with your requirements.

USER: That is ok, thank you for choosing our agency.

ASSISTANT: You are welcome, have a nice day.