Once you've processed all maintenance events that are part of an intervention, you can close the intervention.
To do so you go to the Operational (Beta) dashboard and select the asset connected to the intervention you wish to close. In the pop-up window that appears when you click on the asset in the list, you go to the "interventions" tab and select the intervention you wish to close.
A new pop-up window, containing all the intervention details, will then appear. Scroll down to the bottom of that window and click on the blue "Finish intervention" button.
The 20 last closed (or canceled) interventions will be shown in the interventions overview of the corresponding asset: