You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

USER: Actually, I need to change my existing reservation which is done recently due to health issue, can you please help me out?

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Margaret Allen here.

ASSISTANT: Please wait, I will check the reservation on your name and get back to you.

USER: Sure, I will wait.

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

USER: Ok, not an issue. Thank you for your reservation.

ASSISTANT: Thank you for contacting us.