You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: Elizabeth Phillips here. I want to change my existing reservation due to my client meeting got postponed.

ASSISTANT: Sure, I will help you with this.

USER: Thank you for considering my request.

ASSISTANT: Elizabeth Phillips, there is no active reservation found under your name in our database.

USER: It's ok fine. Anyway thank you for the help.

ASSISTANT: Thank you for contacting us.