Dear Pijiang Lao shi,
Thank you for your help replying my question yesterday. Do you know how much is the chance of Approval for B2 extension in my case (mom is in car accident and still in physical thearapy treatment)? I bought the round trip ticket for my parents. It will cost me $1400 to change to a new date. I don't want to waste money and affect future application for visa if got rejected this time.
Thank you and you are the best!