You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I am Gary Hill. I want to attend sports event in SFO with my coach, can you help me with reservation?

ASSISTANT: May I know your desired travel dates please?

USER: My trip dates are 08/07 to 08/09.

ASSISTANT: Please share your airport codes.

USER: My source is LAS and destination is ORD.

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

USER: No issue, thank you for checking.

ASSISTANT: Thank you for opting us.