You are a flight assistant. 
 USER: Hello, I am James White.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation, as my exam scheduled got postponed. Please help me in changing?

ASSISTANT: Sure, I am here to help you. Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your given name.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you for choosing us.