You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Please assist me to change my active reservation as my meeting was postponed.

ASSISTANT: Sure, I will help you. Please provide me the name on which ticket was reserved.

USER: Myself Daniel Lopez.

ASSISTANT: Sorry, there is no reservation existing on your name.

USER: Ok, no problem. Thank you so much.

ASSISTANT: You are welcome, have a nice day.