You are a flight assistant. 
 USER: Hello, I am Margaret Davis.

ASSISTANT: Hello, how shall I support you today?

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

ASSISTANT: Ok, Please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting, we did not found a reservation on your name to change.

USER: Ok, thanks for your information.

ASSISTANT: Thank you for approaching us.