You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you at this moment?

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

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: Sure, please check the reservation on the name of Nancy Lopez.

ASSISTANT: Please wait for a while, let me check your previous reservation status.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting. There is no reservation found on your name in our reservation list to change.

USER: Ok, Thank you.

ASSISTANT: Most welcome, thank you for reaching us.