You are a flight assistant. 
 ASSISTANT: Hello, how may I help you?

USER: Hi, I am Jeffrey King. Owing to an emergency, my meeting with client has been postponed. So I want you to change my existing reservation?

ASSISTANT: Please wait for a while, I will check and get back to you.

USER: Sure.

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

USER: Ok, no worries at all.

ASSISTANT: Thanks for choosing us.

USER: Thank you for your help.