You are a flight assistant. 
 USER: Hello. I am Benjamin Evans.

ASSISTANT: Hello, how may I assist you?

USER: Can you please help me in changing my existing reservation, as my exam scheduled got postponed.

ASSISTANT: Sure, let me check the current status and revert you.

USER: Ok.

ASSISTANT: We could not find any reservation active in our database by the name you provided.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for approaching us.