You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Amy Evans. I want to attend a food festival at Washington. Can you help me to book a flight ticket in my preferable dates are Nov, 17 and Nov, 19?

ASSISTANT: Sure, we are glad to help you.

USER: Thank you.

ASSISTANT: Which airports do you prefer to travel?

USER: My airport codes are HOU and IAD.

ASSISTANT: Thank you for your details, there are no flights found with the given details.

USER: Ok, no problem. Thank you for information.

ASSISTANT: Thank you.