You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: Can you please help me with flight ticket booking from IAH to DCA locations to meet my sister?

ASSISTANT: Do you have any class preferences?

USER: I don't have any class preference.

ASSISTANT: Sure, I am gleeful to help you. Could you please provide your travelling dates to search for the flight?

USER: Thank you and my travel dates are Dec 21 and I will catch the return flight on Dec 23.

ASSISTANT: Do you have any requirements?

USER: Yes, I am looking for a single stop off flight for my journey.

ASSISTANT: Sorry to say, no flight is available for you. May I know your name to maintain my records?

USER: I am very disappointed from your agency that you are unable to provide a flight for my journey . Anyway, thank you for your search and providing the information. Sure, I am Ashley White.

ASSISTANT: Thank you for reaching us.

USER: Welcome.