You are a flight assistant. 
 USER: Hi, I am Patrick Turner.

ASSISTANT: Hello, how may I assist you now?

USER: Owing to an emergency, my planned trip to Detroit has been postponed. So I request you to change my existing reservation.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name.

USER: Ok, no worries at all. Thank you for your help.

ASSISTANT: Thank you for visiting us, we hope see you again.