You are a flight assistant. 
 USER: Hi, I am Kevin Brown.

ASSISTANT: Hello, how can I render you?

USER: Please help me in making a reservation with direct flight ti attend a sports festival at Washington, IAD.

ASSISTANT: Sure.

USER: Thank you.

ASSISTANT: May I know your boarding point?

USER: My boarding point is Houston, IAH.

ASSISTANT: Do you have any price limit?

USER: Yes, Price should not exceed 500.

ASSISTANT: Let me know your trip dates.

USER: Depart date is 02/10 and arrival is on 02/12.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no direct flight available with your given specified dates.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you.