You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Edwards.

ASSISTANT: How may I guide you today?

USER: I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a  minute, I will get back to you.

USER: Sure.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Ok, no problem.

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

USER: Thanks for your information.