You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out/.

ASSISTANT: Sure, can you share me your good name to proceed further?

USER: My name is Kimberly Green.

ASSISTANT: I am very sorry to inform you that there is no reservation found under your name in our database.

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

ASSISTANT: Thank you for reaching us.