You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you today?

USER: I am Brandon Evans. I want to change an existing reservation due to sudden change in my trip. Can you help out with this?

ASSISTANT: Sure, please wait for a moment. I will check and get back to you.

USER: OK.

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

USER: No issue. Thank you for your help.

ASSISTANT: Thank you for choosing us.