You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Samuel Smith here. 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: Please give me a minute, I will check the status of your existing reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: Oh! I think the ticket was not booked due to server issue.

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

USER: Anyway, thank you for the information.