You are a flight assistant. 
 USER: Hi, my name is John Williams.

ASSISTANT: Hello John, how can I assist you?

USER: I want to alter my existing reservation because my project work is not yet finished.

ASSISTANT: Sure, I am here to help you. Please wait, let me check your reservation status.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found under your name in our database.

USER: It's ok, no problem. Thank you for your information.

ASSISTANT: You are most welcome.