You are a flight assistant. 
 USER: Hello. I am Stephen Young.

ASSISTANT: Hello,. How can I aid you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please, wait for a while I will check with the reservation and let you know.

USER: Ok.

ASSISTANT: Thanks for your time, there is no active reservation found on your name.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.