You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Joshua Lopez. Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Sure. Please wait for a while.

USER: Ok.

ASSISTANT: Sorry to say that, there is no active reservation on your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.