You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

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

ASSISTANT: Sure, we are mirthful to serve you.

USER: Ok.

ASSISTANT: May I know your good name to change your reservation?

USER: I am Kevin Phillips.

ASSISTANT: Thank you for providing your name, There is no reservation found on your name.

USER: No issue.

ASSISTANT: Thank you for opting us.

USER: I will choose another alternative. Thank you .