You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, can you please let me know your name to check with the reservation status?

USER: My travelling dates are Aug 20 and Aug 22.

ASSISTANT: May I know your name to check with the reservation status?

USER: My name is Laura Green.

ASSISTANT: Sorry, there is no active reservation found under your name to amend.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.