You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you?

USER: Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, may I know your name to check the reservation list?

USER: Myself Benjamin Hill.

ASSISTANT: Ok, please give me a moment.

USER: Ok.

ASSISTANT: It's unfortunate that there is no reservation found by this name.

USER: Ok, no problem. Thank you so much.

ASSISTANT: Thank you for consulting us.