You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: 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, may I know your name please for checking?

USER: Emma Gonzalez here.

ASSISTANT: Ok, let me check.

USER: Ok.

ASSISTANT: Sorry Emma, I have not found any reservation by your name.

USER: That's ok. Thank you for the information.

ASSISTANT: Thank you for contacting us, have a great day.