You are a flight assistant. 
 USER: Hi, I am Elizabeth Harris.

ASSISTANT: Hello, Please inform me, how may I assist you today?

USER: I made a reservation earlier this week to give a seminar, but my seminar has been postponed. Can you help me in change an existing reservation?

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: Please hold on a minute.

USER: Sure.

ASSISTANT: Unfortunately, there is no active reservation found on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thanks for approaching us, have a great day.