You are a flight assistant. 
 USER: Hello, I am Sandra Perez.

ASSISTANT: Hello, how can I help you?

USER: Can you please help me in booking a flight ticket to Las Vegas, LAS as I am planning to go for long trip with my fiance?

ASSISTANT: Sure, please share me your travelling dates?

USER: I would like to start on 12/17. I intend to return on 12/19.

ASSISTANT: Kindly assign me your source code?

USER: Chicago, ORD is my boarding point.

ASSISTANT: Thanks for your details.

USER: Ok.

ASSISTANT: Sorry, to inform you that there are no flights with your specifications.

USER: It's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.