You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: Can you please share me your name?

USER: My name is Rebecca Anderson.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

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

ASSISTANT: Thank you for reaching us, have a nice day.