We have a site that has multiple DCs. One dc is the FSMO roles holder (PDC, etc). We need to transfer the roles to the additional domain controller and do not have any issues doing so. The question is what must happen with the server that used to be the PDC. Can this server stay on the domain as an ADC and GC server. The reason for this is a software vendor will not support their software so long as it is installed on the FSMO role holder. It has always been my experience to remove the old PDC from the network and format/reload (change SID) of the box before putting back into the domain. Is this practice needed? I have not been able to find any articles in MS KB to support either argument.