You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Thomas Walker.

ASSISTANT: Walker, how can I aid you?

USER: Book a ticket from DEN to IAD, make sure that could be a direct flight.

ASSISTANT: Please can I know your trip dates?

USER: Sure, my trip dates are 05/27 and 05/29.

ASSISTANT: Sorry, no direct flight is available for you.

USER: It's ok, thanks for checking.

ASSISTANT: You are welcome, have a nice day.