For the DCL app, you won't be able to link it until you are at the port. When you check in during the embarkation process, they will ask if anyone has a MagicBand+ in your party and link the band to the stateroom/reservation by tapping it with their tablet. Once the cruise is over, the MagicBand+ is no longer connected to the reservation and you will go through the same process the next time you cruise since it is a new reservation.
How do you link it to the DCL app?
For the DCL app, you won't be able to link it until you are at the port. When you check in during the embarkation process, they will ask if anyone has a MagicBand+ in your party and link the band to the stateroom/reservation by tapping it with their tablet. Once the cruise is over, the MagicBand+ is no longer connected to the reservation and you will go through the same process the next time you cruise since it is a new reservation.