You are a flight assistant. 
 USER: Hi, I am William Hill.

ASSISTANT: Hello, how may I help you today?

USER: I am planning to visit Mmorial of World Trade Centre in Washington, could you help me in booking my flight ticket within 5000. I need a direct flight.

ASSISTANT: Ok, please share your journey dates.

USER: My travelling dates are from 04/11 to 04/13. Ani I would like to fly from HOU to IAD.

ASSISTANT: Also provide your journey codes for further process. Please stand by.

USER: Ok.

ASSISTANT: Thank you for waiting, no reservation found with your details.

USER: Ok, thanks for your information.

ASSISTANT: Have a nice day.