You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Stephen Martin, I want to change my reservation as my plan to visit my home is postponed. Can you change my reservation?

ASSISTANT: Ok, wait a moment.

USER: Sure.

ASSISTANT: Thanks for your time, there is no reservation found on your name to change it.

USER: Ok, thank you for the information.

ASSISTANT: Thanks for choosing us, hope you have a great day.