You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

USER: I am Charles Young. My graduation day in the college was postponed. I would like to change my existing reservation. Could you please help me?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry, there is no reservation found with your name.

USER: No issues, Thank you for the information.

ASSISTANT: Thank you for choosing us.