As a league administrator you have the choice to edit the permissions team administrators have surrounding fixture alterations. To do this select the setup tab at the top, league options and then team admin results and fixture options.
You can block team administrators from changing the fixture status of a fixture by selecting the top box. Then the four boxes underneath show what the home and away team administrators can edit. Changing the fixture time and venue can only be edited by home team administrators as this is a requirement with The FA Matchday app.