You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donna Garcia here.

ASSISTANT: How can I help you?

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

ASSISTANT: Sure, just a moment please.

USER: Ok, take your time.

ASSISTANT: I am sorry no reservation found on your name.

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.