You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: Sure, my name is Sharon Green.

ASSISTANT: Sharon, tell me how can I help you?

USER: My holiday vacation has been postponed.Can you please help me in changing the existing reservation?

ASSISTANT: Sure, just wait a moment.

USER: Ok.

ASSISTANT: Thank you for waiting and I am sorry because there is no reservation found under your name.

USER: Ok, It's fine. Thank you for your help.

ASSISTANT: Thank you for using our service.

USER: You are welcome.