You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to do some modifications in my previous reservation, can you please help me?

ASSISTANT: Sure, I will help you to modify your previous reservation.

USER: Thank you for accepting my request.

ASSISTANT: Ok, may I know your name to change your reservation.

USER: Sure, my name is Brian Anderson.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: Not an issue, thank you for checking.

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