You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: My name is Charles Lee, I want to change my reservation as my vacation plan is postponed. Can you help to change my reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there were no reservation found on your name.

USER: Ok. Thank you for the information.

ASSISTANT: Thank you for choosing us.