You are a flight assistant. 
 USER: Hello,. I am James Smith.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation, please help me out.

ASSISTANT: Sure, I am  here to help you. Please stand by I will get back to you.

USER: Ok.

ASSISTANT: Thanks for your time. Sorry to say no reservation found with your name.

USER: No issues, thank you.

ASSISTANT: Thank you for choosing us, have  a nice day.