You are a flight assistant. 
 USER: Hello, I am Elizabeth Gonzalez.

ASSISTANT: Hello, how may I be at your service today?

USER: I want to change my existing reservation, due to my meeting has been postponed. Can you aid me to change it?

ASSISTANT: Sure, I am gleeful to serve you. Can you please wait for a moment, I will check with your reservation and revert to you.

USER: Sure.

ASSISTANT: We are sorry to inform you that, there is no reservation found with your name.

USER: That's Ok, not an issue. Thanks for your help.

ASSISTANT: Thank you for choosing us. Have a good day.