You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Katherine Carter here.

ASSISTANT: How can I assist you today?

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

ASSISTANT: Sure, will you please give me a moment?

USER: Thank you, take your time to check.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

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

ASSISTANT: Welcome, have a great day.

USER: Welcome.