You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. How can I be your assistance today?

USER: I want to change my existing reservation because my meeting got delayed. Can you help me with this?

ASSISTANT: Sure, we are here to help you. To change your existing reservation may I know your name?

USER: I am Margaret Walker.

ASSISTANT: Please wait a moment I will check and revert to you.

USER: Ok.

ASSISTANT: Sorry, I found no reservation in your given name.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your quick response.