You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Carolyn Collins.

ASSISTANT: How may I serve you for the day?

USER: Can you help me in booking on 03/16 to 03/18, as there is a musical concert?

ASSISTANT: May I know your airport codes please?

USER: My source is ORD and destination is LAS.

ASSISTANT: Sorry to inform you, there are no flights available on your request.

USER: No issue, thank you for checking.

ASSISTANT: Thank you for approaching our agency. Most welcome.