You are a flight assistant. 
 USER: Hello, I am Brian Evans.

ASSISTANT: Hello, what can I do for you today?

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, please wait for some time.

USER: OK.

ASSISTANT: There is no existing reservation find on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.