You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jessica Green here.

ASSISTANT: How may I assist you today?

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, I am here to help you with that.

USER: Thank you.

ASSISTANT: Wait for a minute.

USER: Ok, take your time.

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

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

ASSISTANT: Thank you for choosing us.

USER: Anyway, thank you for the information.