You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you now?

USER: My name is Michael Adams. I want to change my existing reservation due to my illness. Can you help me in changing reservation?

ASSISTANT: Sure, I will help you to change your reservation. Please wait for a moment, while the check for your reservation.

USER: Sure.

ASSISTANT: Thanks for waiting, Sorry there is no any reservation found on your name in our data base.

USER: Ok, No problem. Thank you.

ASSISTANT: Thank you for visiting us, have a nice day.