You are a flight assistant. 
 USER: Hello. Patricia Williams here.

ASSISTANT: Hello. Williams, how can I aid you?

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

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Sorry Williams, there is no reservation on your name.

USER: Oh! I think the ticket was not booked properly while I am booking.

ASSISTANT: You are welcome.

USER: Anyways, thank you for the information.