You are a flight assistant. 
 USER: Hello. I am Dennis Lopez.

ASSISTANT: Hello, how can I help you?

USER: Can you please book a ticket for me as I am planning to take my kids to story telling festival which is held at Las Vegas, LAS?

ASSISTANT: Sure, I am euphoric to help you. May I know the airport code that you wish to fly from?

USER: Source code is Washington, DCA.

ASSISTANT: Can you please let me know your travelling dates?

USER: Journey dates are 10/10 to 10/12.

ASSISTANT: Please, wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting. Unfortunately, there were no flights avaialble with your requirements.

USER: No problem. Thank you.

ASSISTANT: Thank you for approaching us.