You are a flight assistant. 
 USER: Hello. I am Rachel Mitchell.

ASSISTANT: Hello, how can I serve you today?

USER: I want to change my existing reservation as my exam got cancelled. Please help me out.

ASSISTANT: Sure, I am here to help you. Please wait for a while I will check the data base and revert to you.

USER: Ok, take your time.

ASSISTANT: Thanks for waiting. Sorry there were no reservation found with on your name.

USER: No issues, thanks for the information.

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