In case of multiroom connections .. one cannot replace the primary box .. cos ur primary box's ID is linked to ur packages .. So they will drop the other box and add the HD box to it ..Either way its not a prob .. isn't it? U just need to get the connection running on both boxes and then use whtever box at any tv set of urs ..Also if u just have a single connection then its not an issue at all .. cos they will just replace the old box with new one .. They will use the same digicard (of the old box) ..