You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: My visit to the World of Coca-Cola has been postponed, due to my visa problem. For this, I want to change my reservation with the name of John Martinez.

ASSISTANT: Sure, please wait for a moment.

USER: Thank you, I will wait.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem. Thank you for your kind information.

ASSISTANT: Thank you for opting us.