Standard users in Windows 8 are allowed to change their PINs and passwords. We shall teach you how to allow or prevent standard users in Windows 8 to change the passwords of unlocked drives. You must be signed in as an admin or have admin rights in order to perform this tutorial.
1. Open up local Group Policy Editor through Metro Menu as shown below.
2. In the left pane, expand Computer Configuration, Administrative Templates, Windows Components, BitLocker Drive Encryption, and then open Operating System Drives. Now double click on Disallow standard users from changing the PIN or password
3. To Allow Standard Users to Change BitLocker PIN or Password, select Disabled and To Prevent Standard Users from Changing BitLocker PIN or Password, select Enabled. When done, click OK