You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: Owing to an emergency, my meeting with client got postponed. So I want you to change my existing reservation.

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name in our records.

USER: Ok, not an issue.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your help.