You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Steven Scott.

ASSISTANT: How may I be of your help?

USER: I need to change my existing reservation, as my exam scheduled has my been postponed.

ASSISTANT: Ok.

USER: Please help me in changing?

ASSISTANT: Sure, please standby.

USER: Ok.

ASSISTANT: Sorry, we do not found any active reservation with your name.

USER: Ok, no issues.

ASSISTANT: Thanks for approaching us.

USER: Thanks for your service.