When a fixture is still in the future the fixture status can be set to Postponed or Cancelled using the Fixture Status drop down box (see 13 in the illustration below)
Note: If the fixture has already been played or was abandoned or postponed on the day, it is possible to use the Result Details Edit button (button 6) and then force the Result using the drop down list to “Postponed” or “Cancelled” or “Withdrawn” or “Abandoned” etc.
More details about the Fixture & Result Editor can be found here >>>