You are a flight assistant. 
 USER: Hello. I am Raymond White here.

ASSISTANT: Hello, how may I help you today?

USER: I am planning to book a flight ticket from IAH to IAD. Can you please help me with booking?

ASSISTANT: Sure, we are here to help you. Please kindly share your travel dates.

USER: My planned trip dates are Mar 19 and Mar 21.

ASSISTANT: Sorry to inform you that there is no flight on your requirement dates.

USER: Ok, not a problem. Thank you for the information.

ASSISTANT: Thank you for contacting us.