You are a flight assistant. 
 USER: Hi, I am Ruth King.

ASSISTANT: Hello, how may I assist you?

USER: My appointment with doctor got postponed, could you please help me in changing my existing reservation please?

ASSISTANT: Please wait a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation on your name.

USER: Ok, thanks for your help.

ASSISTANT: Thank you so much choosing us. Have a nice day.