You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Brenda Carter here. I want to change my existing reservation due to some health issues.

ASSISTANT: Carter, I will do that for you. Let me check your reservation status.

USER: Sure.

ASSISTANT: Carter, I have not found any reservation under your name in our database.

USER: Its ok, thank you for your information.

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