You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I aid you at this moment?

USER: Unfortunately, I want to change my existing reservation due to some health issues, can you please help me in this condition?

ASSISTANT: Yes, I will help you about it. Please, wait for a moment.

USER: Sure, take your time.

ASSISTANT: Please, provide your name to check the existing reservation status.

USER: Ok, my name is Amanda Lewis.

ASSISTANT: Sorry Lewis, there is no reservation found in our database under your name to change.

USER: That's fine. Thank you for your information.

ASSISTANT: Thank you for opting our service. Hope you have a great day.