You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I am Nicole Roberts. I want to book a  direct flight ticket to Houston. Please help me out.

ASSISTANT: Sure, let me know your airport codes.

USER: I want to fly from IAD to HOU.

ASSISTANT: Could you please share your travelling dates?

USER: My travelling dates are from 11/28 to 11/30.

ASSISTANT: Sorry to say that, no flights were found on your desired route.

USER: No issues, thank you.

ASSISTANT: Thank you for choosing us.