You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Could you please change my existing reservation?

ASSISTANT: Sure, may I know your name to check your reservation from our database?

USER: My name is Edward Hernandez.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: We regret to inform you that there is no active reservation found on your name to change.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for opting us.