You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Andrew Smith want to attend a conference at Los Vegas, can you help me to book a direct flight?

ASSISTANT: Sure, I am happy to help you. Can you please provide your travel dates?

USER: Sure, my travelling dates will be 08/09 and 08/11.

ASSISTANT: May I know your airport codes please?

USER: Yes, I want to have my journey from IAD to LAS.

ASSISTANT: Do you have any connection limit?

USER: Yes, I need a flight with connection 0.

ASSISTANT: Please wait for a while, I will check and get back to you.

USER: Ok.

ASSISTANT: Unfortunately, no flight found on your given details.

USER: That's fine, thank you.

ASSISTANT: Thanks for choosing us.