You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Please change my existing reservation due to my health issue.

ASSISTANT: Sure, provide me your name?

USER: My name is Christopher Mitchell.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found with your name.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for reaching us.