You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Donald Nelson. May I know if you help me to change the reservation I had recently booked?

ASSISTANT: Sure, please wait for a moment.

USER: Ok, please take the time you need.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: That is ok, thank you for assisting me.

ASSISTANT: Thank you.