You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I will help you with that.  Can I have your  good name please to check your reservation status?

USER: Margaret Jones.

ASSISTANT: Ok,  please wait a  moment.

USER: Ok, I will wait.

ASSISTANT: Sorry Margaret Jones, no reservation has found under your name to change.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing us, have a good day.