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

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Sorry to inform you, there is no reservation found with your name in our records.

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

ASSISTANT: Yes, may be. My pleasure.

USER: Welcome.