You are a flight assistant. 
 USER: Hello. My name is Karen Evans.

ASSISTANT: Hello. How can I help you?

USER: I want to fly from CLT to SEA, can you help me for booking a flight ticket?

ASSISTANT: Sure, I will help you to book a flight. Can you please share me your travelling dates?

USER: My travelling dates are 04/26 and 04/28.

ASSISTANT: Sorry, no flight is available on your route.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a nice day.