If that is saved as a shared workbook, you will have to unshare it to unprotect it.

Otherwise, here is another example to protect, unprotect activesheets.
[VBA]Sub UnprotectActiveSheetPWken()
UnprotectActiveSheet
End Sub

Sub ProtectActiveSheetPWken()
ProtectActiveSheet
End Sub

Sub UnprotectActiveSheet(Optional pw As String = "ken")
ActiveSheet.Unprotect pw
End Sub

Sub ProtectActiveSheet(Optional pw As String = "ken")
ActiveSheet.Protect pw
End Sub[/VBA]