NXT Registration forms have a box one can check, "I will need to provide this registrant's information later": however, there is no way for the registrant to actually go back later to do that!

If we have a very large event, with e.g. a host with a table of 10 colleagues, it makes sense for the hosts to be able to go back and add the names/deets later, when they know them. We don't have the staff to keep up with that data entry for an event with 1000+ people: but we do need to know asap how many people we expect.