You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Gary Rodriguez  here, I want to reserve my ticket from IAD to ORD, can you please help me?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, my preferable dates of journey are from Jul, 11 to Jul, 13.

ASSISTANT: Do you have any specifications?

USER: Yes, I need a business class.

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

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for opting us.