You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I need you to book a flight ticket from DCA to DFW. Please help me.

ASSISTANT: May I know on which dates you are willing to travel?

USER: February 20 and 22 are my planned travelling dates.

ASSISTANT: Do you require any stopovers in your journey?

USER: Yes, I need a break in my journey.

ASSISTANT: Do you have any other requirements?

USER: I prefer to fly in a normal-cost airlines.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: That's ok. My name is Cynthia Turner. This might be useful for you. Thank you.

ASSISTANT: Thank you.

USER: You are welcome.