Most people do not know this but you can book next cruise certificates on board that are refundable. The sweet spot is the 7 night balcony sailings. Instead of getting $100 OBC you get $75 OBC and its refundable. This works well for those transferring to a TA who has lower group rates. You get the extra $75 OBC and get to keep the booking refundable, transfer it to your TA, get the group OBC and the lower rate. The only thing you do not get is a reduced deposit which if you were moving it into the group for a lower rate you would have to increase the deposit anyway as group bookings must have a full deposit not the reduced deposit.