Step 1 – First Open the Metro App and choose the App for which you want to change Permissions.
(For Example we are selecting Calender App)
Step 2 – Now Open the Charms Bar by pressing the Windows + C, then go to the Settings Charm.
Step 3 – Click on Permissions at the top of the Right Pane.
Step 4 – Turn permissions ON or OFF according to your requirements for the selected Metro App.
Step 5 – That’s It! Now you can return to Start screen and set Permissions for other Metro Apps by using Same method