You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to bad health conditions. Can you help me in doing that?

ASSISTANT: Sure, I am here to help you. Can I know your name to proceed?

USER: Thank you.

ASSISTANT: No reservation found on your name in my database.

USER: I am Alexander Hernandez. Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us, have a nice day.