You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation which is with the name Virginia Roberts as my plan to visit a function got postponed.

ASSISTANT: Ok, please wait I will check the present status and revert you.

USER: Ok, sure.

ASSISTANT: Thank you for waiting, no reservation found with your name.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for choosing us, have a nice day.