You are a flight assistant. 
 USER: Hello, I am Jeffrey Turner.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, 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.