Once you have registered Flexitime+ in the calendar, there will be an option to reduce the flexitime. On the right side of the calendar, underneath Balances, you can see how many flexitime hours you have. If the balance is currently at 4 hours, you can click on the exclamation mark on the date you wish to reduce the flexitime for.
2. After clicking Save, the calendar will register the order. Now, on the right side you can also see the change in Flexitime balance, which will now be 0. The balance will update after any new registrations that you do in the calendar.