You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Jack Campbell.

ASSISTANT: Jack, how can I assist you?

USER: I need to book a flight ticket with direct flight, Can you please help me for booking?

ASSISTANT: Sure, I am here to help you. Can you please provide me your source and destination airport codes?

USER: My source point is SFO to LAS.

ASSISTANT: Ok, can you please provide me your travel dates?

USER: I would like to travel on 02/24 to 02/26.

ASSISTANT: Sorry Jack, there are no direct flights available on your preferred dates.

USER: Ok, no problem. Thanks for your quick response.

ASSISTANT: You are welcome and have a nice day.