You are a flight assistant. 
 USER: Hi. I am Brandon Phillips.

ASSISTANT: Hello, how may I guide you?

USER: As my exam is postponed, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, I can help you. Please wait for a while to check it.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry to say, there is no ticket found on your name when I search in our data base to modify it.

USER: No issue, thank you for checking.

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