You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My friends have planned to celebrate Columbus day on 10/09 in Houston, TX - IAH. So I want to start from Las Vegas, NV - LAS on 10/08. Please book a ticket for me?

ASSISTANT: Sure, please wait I will let you know the availability of flight.

USER: OK.

ASSISTANT: Thanks for waiting. Sorry, no flights were available on your specified dates. Could I know your name Please?

USER: Sure, I am Donna Hernandez.

ASSISTANT: Thank you,have a nice day.