You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Joshua Lopez. I am planning to change an existing reservation, due to some work.

ASSISTANT: Sure, give me a  minute.

USER: Can you please change my reservation?

ASSISTANT: Sorry, there is no reservation found under your name.

USER: That's fine. Thank you for your help.

ASSISTANT: Thank you for reaching us.