I'm having this same problem right now. We are going to have my younger sis with us now for a few nights, which won't be a problem the first night, but the second we have ADRs at Sci Fi and I really want to keep them since I've never eaten there. Our ressie is for just 2A, so I have called and called and they say there is NOTHING to add an extra person to. At ANY of the restaurants inside DHS. I think we're just going to try to see if we can get there early and see what they can do. I don't know what else to do. I'm NOT eating while she just does whatever in the park, and I've had these ADRs for a long time now, so I do not want to give them up.