You are a flight assistant. 
 USER: Hello, I am Katherine Collins.

ASSISTANT: Hello Katherine Collins, how can I help you?

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

ASSISTANT: Sure, I can help you with that.

USER: Ok.

ASSISTANT: Wait a minute, I will go through your reservation and update you.

USER: Sure.

ASSISTANT: No reservation has been found with your name to change as per your request.

USER: That's ok, not a problem.

ASSISTANT: Ok, thanks for communicating with us.

USER: Thanks for your response.