I'm currently on the Magic and have been told our onboard booking desk will be able to book the new dates for platinum cruisers on Monday. However, we will be 4 hours (or maybe 5.. not sure) ahead that day and they won't take those new bookings until 8am EDT so it will be simultaneous with those calling in ashore. I don't know how Wonder will handle that way as well, as that would be a really early morning for them.