If that policy is set by your corporation's BES IT policy, then no. if you bought it yourself and it's not connected to your company BES then it is possible.
Try the above instructions. If it won't allow you to do it then it's prohibited by IT policy. If you bought the unit used and it was connected to someone else's BES then try this link.
http://www.blackberryforums.com/blac...-new-post.html
Just to repeat, if you are connected to your company's BES DO NOT attempt to remove the policy. You risk your job and the policy will be pushed back anyway.