我的485被拒信上寫著，你可以在一個月之內到local office reopen the case.

I went there and was able to reopen the case. Mine was because we didn't show up for the interview. The letter was late. My suggestion to you is: if you can reopen the case, ask for some document to prove it. My case was reopened but not update to the INS system, so we couldn't renew the EAD. And that was why I went to the local office for the second time. Because I didn't have anything to prove the case was reopened. The security guard ordered me to leave the building. Good luck.