You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you today?

USER: Please help me out with changing my reservation due to sudden health issue.

ASSISTANT: Sure, I'll try to help you in existing reservation.

USER: Thank you for accepting my request.

ASSISTANT: May I know your name to check the reservation status?

USER: Ok, I have reserved on the name of Michael Green.

ASSISTANT: Thank you for providing your name, give me some time to check the reservation list.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry, there is no active reservation have been found under your name in our database to amend it.

USER: It's alright. It might not done due to server issue. Anyway, thank you for the information.

ASSISTANT: Thank you for availing us.

USER: Welcome.