You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation under the name of Michelle Brown. Can you help me out in this?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: There is no reservation on your name.

USER: It's ok, not an issue. Thank you for your response.

ASSISTANT: Thank you so much for choosing us.