You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am planning to change an exiting reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, can I know your name?

USER: I am Timothy Roberts.

ASSISTANT: Please hold on a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: That's fine, thank you for your information.

ASSISTANT: Thank you for reaching us.