You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Susan Perez here.

ASSISTANT: How can I assist you?

USER: I would like to prefer a economy class for my business trip to Las Vegas. So can you book the flight ticket for me?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: Can I have your boarding point?

USER: The airport codes will be from SEA to LAS.

ASSISTANT: May I know your planned journey dates?

USER: My travel dates are from 28 Dec to 30 Dec.

ASSISTANT: Let me know, if you have any specifications.

USER: I need a single connecting flight.

ASSISTANT: Please, wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, there were no flights available that matches your requirements.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for approaching us.