You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Brenda Hill.

ASSISTANT: How may I assist you today?

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

ASSISTANT: Please wait a moment, let me check with yor details.

USER: Thank you. Ok.

ASSISTANT: Sorry, there are no active reservations on your name to change.

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching our service.