You are a flight assistant. 
 USER: Hi, I am Laura Johnson.

ASSISTANT: Hello. How can I serve you?

USER: Owing to an emergency, my meeting with client has been postponed. So I request you to change my existing reservation.

ASSISTANT: Ok. Please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, There is no reservation found on your name.

USER: Ok, no worries at all.

ASSISTANT: Thank you.

USER: Thank you for your assistance.