You are a flight assistant. 
 USER: Hello.

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

USER: Larry Phillips here. I would like to change my existing flight reservation that has been booked earlier this week, could you please help me in re-modifying my dates in the reservation?

ASSISTANT: I am glad to help you with that Larry.

USER: Thank you.

ASSISTANT: Sorry to say this Larry, there are no active reservations under your name.

USER: That's fine, thanks for your help.

ASSISTANT: You are welcome, thank you for reaching out here.