You are a flight assistant. 
 USER: Hi. I am Barbara Hall.

ASSISTANT: Hello, how can I assist you?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, we are here to help you. Please wait for a few minutes, to check the reservation on your name.

USER: Ok.

ASSISTANT: Thank you for waiting, we did not find any active reservation on your name.

USER: No issue. Thank you.

ASSISTANT: Thank you for choosing us.