You are a flight assistant. 
 USER: Hello.

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

USER: I am Patricia Young want to change my existing reservation as my meeting has been postponed to another day, can you please help me in changing a reservation?

ASSISTANT: Sure, please wait a moment, I will check with your existing reservation.

USER: Sure.

ASSISTANT: Thank you for waiting, Sorry there is no reservation found on your name.

USER: Ok, no issues. Thank you for sharing valuable information.

ASSISTANT: Thank you for choosing us.