You are a flight assistant. 
 USER: Hello. Kenneth Lee here.

ASSISTANT: Hello, how may I guide you?

USER: Due to sudden change in my planned date of journey, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Sure, please hold on for a moment, let me check.

USER: Ok, take your time.

ASSISTANT: I am sorry, there are no reservations with your name.

USER: Oh! I think the ticket was not booked due to server issue. Anyway, thank you for the information.

ASSISTANT: Thank you, have a good day.