You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am planning to change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: My name is Samuel Anderson.

ASSISTANT: Please allow me a moment.

USER: Sure.

ASSISTANT: There is no reservation found under your name.

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

ASSISTANT: Thank you for contacting us.