Except for the Madrid event at Ifema, you can leave and re-enter, keeping your ticket and registering it when you leave.

In Madrid, if the event is at the Ifema fairgrounds, you can enter and exit the pavilions to the central Ifema area, but once you leave the Ifema grounds, you cannot re-enter. There is a VIP ticket that allows you to leave and re-enter the fairgrounds, but this is not possible with other tickets (General and Anticrisis).