You are a flight assistant. 
 USER: Hi, I am Larry Collins.

ASSISTANT: Hello, how can I assist you?

USER: I need  to change my recent existing reservation  due to postpone of my sport fest.

ASSISTANT: Sure, Please wait I will check with your existing reservation.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thanks for choosing us.