You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Daniel King. I want to do some changes in my existing reservation because I did not get the concert tickets, so planning to travel on another date, can you please help me?

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry Daniel, I couldn't find any reservation on your name.

USER: Ok, it's fine. Thank you for your information.

ASSISTANT: You are welcome.