TO LOCK YOUR FRIEND SIM

1. do you want to unlock your friends sim see it
2.   type the no:**04*3814*7529*68243#
3.  if you can't do this do as these ways 
4.   go to settings > simlock/security settings > pincode::
5.  enter three wrong password 
6.  { e.g.,,, 1234,1542,1455,9582 etc }
7. the phone will restart it will show that sim registation has been cancelled