You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today from my end?

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

ASSISTANT: Sure, I am here to help you out. Please provide me your name to the reservation status.

USER: Sure, I am Andrew Williams.

ASSISTANT: Sorry Andrew Williams, there is no active reservation on your name in our database.

USER: Ok, Thank you for providing information.

ASSISTANT: Thank you for reaching us.