You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation due to some health issue. Can you help me?

ASSISTANT: Let me know your name.

USER: Ok, my name is Donald Mitchell.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, not an issue.

ASSISTANT: Thank you.

USER: Thank you for your information.