You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: I am Brain Robinson. Owing an emergence, I want to change my existing reservation.

ASSISTANT: Sure, I will help you with that Brian Robinson.

USER: Ok.

ASSISTANT: Please wait for sometime to check the active reservation with your name in our booking list.

USER: Sure.

ASSISTANT: I regret to say this Brain Robinson, there is no active reservation with your name in our booking list to change your reservation.

USER: That's ok, thanks for the information.

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