You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello.

USER: I am Daniel King.

ASSISTANT: How can I help you?

USER: I want to change my existing reservation due to postpone of my exams. Can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: Sorry to say no reservation found on your name.

USER: Thanks for your kind response.

ASSISTANT: Thank you for reaching us, have a nice day.