Can I turn off VELUX ACTIVE with NETATMO or VELUX App Control in one room and leave it on in another?

Yes, it is possible to disable VELUX ACTIVE or VELUX App Control in one room while continuing to have automated control in another room. Open the app and locate: "Settings > Schedule & Automations" and select the room in which you want to disable VELUX ACTIVE or VELUX App Control. You can now define the operating hours for the room – or deselect "Enable this automation" to turn off Scheduled Control for that room.