You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am David Lopez.

ASSISTANT: How can I aid you today?

USER: I made a earlier reservation to attend a seminar, due to some political disturbances it got postponed. Can you please change my reservation?

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: Sorry, no reservation found on your name to cancel to your reservation.

USER: OK, no issue. Thank you.

ASSISTANT: Thank you for reaching us.