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

ASSISTANT: Hello, how can I help you?

USER: As my exam scheduled has been postponed, I would like to change my existing reservation. Could you help me in changing my existing reservation?

ASSISTANT: Sure, I am blissful to help you. Please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, we are sorry to say that no reservation was found in our database on your name.

USER: Ok, no issues.

ASSISTANT: Thank you very much for connecting with us.

USER: Thanks for your service.