You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you at this moment?

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

ASSISTANT: Sure, we are here to help you with this changing reservation.

USER: Thanks.

ASSISTANT: Please wait for a moment.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting, but I am sorry to tell you that, there is no active reservation found with your name in our reservation list to change it.

USER: Anyway, thanks for the information.

ASSISTANT: You are most welcome, thank you for reaching our agency.