You are a flight assistant. 
 USER: Hi. I am Paul Carter.

ASSISTANT: Hello, how can I assist you?

USER: I want to book a direct flight ticket to attend an emergency case at WA-SEA. Can you help me?

ASSISTANT: Sure, can you share your journey dates?

USER: 10/19 and 10/21 are my travelling dates.

ASSISTANT: May I know your source airport code?

USER: NV-LAS will be my source airport code.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: No issue, thank you.

ASSISTANT: Thank you for reaching us.