You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Brenda Hill.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Sorry Brenda, there is no active reservation found with your name in our records.

USER: Ok, no issues. Thank you.

ASSISTANT: My pleasure.