You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Robert Wilson.

ASSISTANT: Hi Robert.

USER: Can you please help me to book a ticket from AZ-PHX to NV-LAS?

ASSISTANT: Ok, when would you like to travel?

USER: My travelling dates are 12/11 and 12/13.

ASSISTANT: Sorry Wilson, unfortunately there is no flight with your requested dates.

USER: Ok, thak you for your information.

ASSISTANT: Thank you, have a good day.