You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I am Christopher Green. I want to book a flight ticket to Washington to attend a music festival, please help me out.

ASSISTANT: Sure, Can you please share your planned trip dates?

USER: My travelling dates are from Aug 16th to Aug 18th.

ASSISTANT: Kindly, mention airport codes.

USER: I want to fly from IAH to IAD.

ASSISTANT: Do you have any specifications?

USER: I need the ticket with a lay by within the journey.

ASSISTANT: Sorry, there are no flights found on your specified routes.

USER: No issues, thanks for the information.

ASSISTANT: Thank you.