You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Ryan Adams. I am planning to travel from IAD to DEN for a business meeting, can you please help me with booking a flight ticket?

ASSISTANT: Sure, can I know your travelling dates?

USER: My travelling dates are 09/25 and 09/27.

ASSISTANT: Ok, give me a moment.

USER: Sure.

ASSISTANT: Sorry to say that there are no flights found matching your requirement.

USER: That's ok.

ASSISTANT: Sorry for the inconvenience.

USER: Thank you for the information.

ASSISTANT: You are welcome.