You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Janet Davis.

ASSISTANT: How may I help you out?

USER: Please help me with changing my reservation.

ASSISTANT: Sure. Please hold on, for a while.

USER: Ok.

ASSISTANT: Thanks for your time, no reservation is existed to proceed with changing the reservation.

USER: Fine, thanks for the information.

ASSISTANT: Thank you for choosing us.