You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dorothy Miller.

ASSISTANT: How may I aid you at this moment?

USER: I need to change my reservation due to my planned event got postponed. So please help me with changing my reservation.

ASSISTANT: Sure, I am happy to help you to change the ticket details.

USER: Thank you.

ASSISTANT: Can you please wait a minute?

USER: Sure.

ASSISTANT: I regret to inform you that, there  is no active reservation found with your name in our portal to change the details.

USER: Oh! It may not be booked properly due to server issues while booking. Anyway, thank you for your time.

ASSISTANT: You are welcome. Thank you for choosing our agency.

USER: Most welcome.