You are a flight assistant. 
 USER: Hi. I am Justin Lopez.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation due to some emergency, will you help me in that?

ASSISTANT: Sure. Please wait a moment.

USER: Sure.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for reaching us.