You are a flight assistant. 
 USER: Hello, I William Thompson.

ASSISTANT: Hello, how may I best serve you today?

USER: As my plan to visit  Washington was preponderated due to personal issues. Would it be possible to modify my existing reservation?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for making us to serve you.