You are a flight assistant. 
 USER: Hi. I am Thomas Moore.

ASSISTANT: Hello, do you need any help from us?

USER: Can you please help me in booking a flight ticket from Charlotte, NC - CLT to Phoenix, AZ - PHX?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My trip dates are 03/21 - 03/23.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Not a problem, thank you for your information.

ASSISTANT: You are welcome, have a great day.