You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Timothy Lewis here. I need to attend a business meeting at Philadelphia, can you please help me in booking a flight ticket from ORD to PHL?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, my travel dates are from 08/23 to 08/25.

ASSISTANT: Please wait a while, I will check and inform you.

USER: Ok, I will wait for your response.

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

USER: Ok, no problem. Anyway thank you for the information.

ASSISTANT: Thank you for opting us.