Yes, he would need to file a 1040X to remove you. Along with that, if there were any credits, they will be removed as well. He will need to repay any refund he was not entitled to. You do not need to wait for any specific notice that the IRS received the amended return. You will, however, need to mail your return. It will not e-file with you having already been claimed. The amendment will not allow you to e-file.
