You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Steven Collins.

ASSISTANT: How may I serve you today?

USER: Can you please change my existing reservation as my plan to go for holiday trip got postponed?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation on your name to change.

USER: It's ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for opting us.