You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Samuel Nelson here. I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, wait a minute.

USER: Ok, take your own time.

ASSISTANT: Sorry, we could not find any reservation on your name.

USER: Not a big problem, anyway thank you for the information.

ASSISTANT: Thank you for opting us.