You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Katherine Clark here.

ASSISTANT: Clark, how may I assist you?

USER: I want to cancel my ticket as I am sick.

ASSISTANT: Sure, I will help you. Let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry Clark, there is no reservation found under your name in our database.

USER: No problem, thank you.

ASSISTANT: You are welcome and thank you for choosing us.