It's possible to update the limit number of slots for an event occurrence, based on an occurrenceUuid. This number of slots cannot be reduced below the number of active reservations (slots). In the occurrenceUuid property of occurrences*, each occurrence* is represented individually.
If the event occurrence has a seat map, you can also use this endpoint to update the occurrence's list of available positions. To do this, you must enter the new updated list of positions external references to the availablePositions field.