To change the status of multiple events at once, select the events you wish to change using the check boxes.
NOTE
"Changing the selected event to "Completed" for a "Completed" event does not change the status of the event.
The status will not change even if you select "Change selected event to 'Processing'" for an event that is "Processing".
Select some events
Open [ Menu ] > [ Event List ], check each event (①) whose status you want to change, and click 
to change the status. (②)
Select all events
Check the checkbox (①) shown below and click to change the status. (②)
