You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Sarah Williams here.

ASSISTANT: How can I assist you at this moment?

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

ASSISTANT: Sure Sarah Williams, I will help you with that.

USER: Thanks for that.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Ok, I will wait.

ASSISTANT: Sorry Sarah Williams, 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.