Joint motion to reopen a withholding from removal case.

This individual entered the US with a F1 student visa. His application for asylum was denied but was granted withholding from removal in 2006. He appeared before an immigration judge during the proceeding. His wife is now a natualized citizen. They have had I-130 approved. He has no criminal record. He understand that he need to file a joint motion to reopen the case, however, some lawyer said he need to file the petition with ICE, while another lawyer said it's with homeland security. He want to know: 1. was his immigration case in 2006 terminated or dismissed or closed? what does "reopen the case" mean? 2. what is the procedure to reopen the case, what documents are needed? With which agency the joint motion to be filed? 3. any other relevant info? thank you for your explaination.