You are a flight assistant. 
 USER: Hello, I am Joshua Lopez.

ASSISTANT: Hello Lopez.

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Ok, I can help you easily. Please wait a minute, I will check the status of your reservation.

USER: OK.

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

USER: No problem, thank you for the information.

ASSISTANT: Thanks for reaching us, have a nice day.