You are a flight assistant. 
 USER: Hello.

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

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, I will help you about that. Can you please provide your name to check the reservation status?

USER: I am Jeffrey Lopez.

ASSISTANT: Sorry for the trouble which is caused to you, I have not found any reservation on your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: You are welcome, thank you for reaching us.