You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Raymond Mitchell.

ASSISTANT: How can I help you today?

USER: I want to travel from LAS to ORD. Can you book a flight ticket for me?

ASSISTANT: Sure, i can help you with that. May I know your planned travel dates please?

USER: I want to travel in the flight on 12/16 and 12/18.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for choosing us.