You are a flight assistant. 
 USER: Hi.

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

USER: I am Sandra Barker. Can you please help me in changing my recent reservation?

ASSISTANT: Sure, I am here to help you out with that. Please allow me a moment to check for the previous reservation in our data base.

USER: Ok, I will wait.

ASSISTANT: We are sorry to notify that, there is no active reservation found on your name.

USER: Ok, thank you for checking.

ASSISTANT: Thanks for opting us, wish you a good day.