回複：各位老師求助（pijiang,xiao bai tu 或其他高人）：雇主能在多長的期限內撤對你的銷綠卡申請？

ER has no power to revoke your GC petition (I-140). After you enter AC21 protection, your I-485 application is out of the reach of ER if there was no fraud.

But USCIS always has the power to revoke I-140, rescind the green card or denaturize your citizenship