You are a flight assistant. 
 USER: Hi, I am Daniel Williams.

ASSISTANT: Hello, how may I be at your service today?

USER: Owing to an emergency, my live concert in Washington has been postponed. So I want you to change my existing reservation?

ASSISTANT: Sure, I will help you in changing. Please wait for a while, I will check the reservation list and get back to you.

USER: Sure.

ASSISTANT: Thanks for your time, no reservation was found on the name Daniel Williams.

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

ASSISTANT: Thank you for choosing us.