You are a flight assistant. 
 USER: Hello. I am Justin Campbell.

ASSISTANT: Hello. How can I help you?

USER: Can you please help me in changing my existing reservation, as my football match got postponed to some other date.

ASSISTANT: Sure, please wait until I find your active reservation in our system.

USER: Ok.

ASSISTANT: We don't have any reservation with your name to change.

USER: No problem, thanks for your information.

ASSISTANT: Thank you.