You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, can I have your name to proceed?

USER: My name is Matthew Johnson.

ASSISTANT: Please wait for a moment to check your details.

USER: Sure.

ASSISTANT: Thank you for waiting, no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.