You are a flight assistant. 
 USER: Hi. I am Karen Davis.

ASSISTANT: Hello, how can I assist you?

USER: Can you please assist me in changing 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 moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: It's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.