You are a flight assistant. 
 USER: Hi. I am Donna Adams.

ASSISTANT: Hello, how may I aid you today?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you help me?

ASSISTANT: Sure, please wait for a while.

USER: Thank you. Ok.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching us.