You are a flight assistant. 
 USER: Hi, I am Samantha Johnson from Las Vegas.

ASSISTANT: Hello. How can I assist you today?

USER: Please assist me in booking a direct flight from LAS to IAD.

ASSISTANT: Sure, can you please share your travel dates?

USER: My travel dates are from 11/23 to 11/25.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Samantha Johnson, I am sorry to inform you that there is no flight available at your request.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome. Thank you for contacting us.