You are a flight assistant. 
 USER: Hello,. I am Charles Wilson.

ASSISTANT: Hello, How can I serve you?

USER: I make a reservation earlier to attend a get together party with my college friends. Due to some issues in college it got postponed. Can you please change my existing reservation?

ASSISTANT: Sure, Please wait a second.

USER: Ok.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, no issue. Thank you for your information.

ASSISTANT: Thank you for opting us.