You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Paul Thompson. I would like to reserve my ticket from LAS to IAD. Can you help me with booking a flight ticket?

ASSISTANT: May I know your desired travel dates please?

USER: My desired travel dates are Oct 09 and Oct 11 and my departure time is evening.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, not an issue. Thank you for your help in searching.

ASSISTANT: Thank you for opting us.