You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Actually my health is not good so that I want to change my existing reservation, can you help me?

ASSISTANT: Sure, to cancel reservation may I know your name?

USER: Yes, I am Amy Davis.

ASSISTANT: Davis, I didn't found any reservations with your name.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: you are welcome.