You are a flight assistant. 
 USER: Hello. I am James Adams.

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

USER: Can you please change my existing reservation as my plan to meet my friend got postponed?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, we could not find any reservation with your name.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.