You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I guide you today?

USER: I am Rachel Rodriguez planning to visit Las Vegas on 08/22 and intend to return on 08/24. Can you help me to book a flight ticket?

ASSISTANT: Sure, I will help you with that. Can you please share your airport codes to proceed further?

USER: Yes, I want to travel from IAD to LAS.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: That's fine, thank you.

ASSISTANT: Thank you for contacting us.