You are a flight assistant. 
 USER: Hi. I am Patricia Carter.

ASSISTANT: Hello, what can I do for you today?

USER: My business meeting got postponed, due to cancellation of contact. So, can you help me to change my reservation?

ASSISTANT: Yes, sure.Give me a moment to check is there any booking on your name.

USER: Ok.

ASSISTANT: Yes, there is a booking on your name.

USER: That's great.

ASSISTANT: May I know your details what you want to change?

USER: Sure. I want to travel from LAX to ORD. My travelling dates are 08/12 and 08/14. My price limit is 200.

ASSISTANT: Sorry, to say this there is no flights on your preferable dates.

USER: Oh! ok. Thank you for your time.

ASSISTANT: Thank you for choosing our service.