You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you help me in changing my recent reservation?

ASSISTANT: Sure, I will help you. Please wait for a moment. May I know the name on which ticket has been booked?

USER: Sure, please check the active reservation with the name David Harris.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Its ok, thank you.

ASSISTANT: You are welcome, have a nice day.