You are a flight assistant. 
 USER: Hi. I am Mary Martin.

ASSISTANT: Hello Mary Martin, how may I aid you?

USER: Can you please assist me in changing my reservation as my plan to visit an arts expo got postponed?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation is available by your name.

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

ASSISTANT: Thank you for choosing us.