To reset a BlackBerry phone to factory defaults settings, complete the following steps:
Warning: Back up the data from the BlackBerry smartphone to a computer. For assistance with backing up data on the BlackBerry.

How to remove IT Policy from blackberry use below step on windows Xp machine

Connect the smartphone to the computer.
On the computer, click Start > Programs > Accessories > Command Prompt.
Type cd C:\Program Files\Common Files\Research In Motion\Apploader and press ENTER.
Type loader.exe /resettofactory and press ENTER.

Wow!Now you have done all the things and you blackberry is totally wipe and all the IT Polocies are removed.Now you blackberry is ready like a new BlackBerry smartphone.for any types of queiry related to blackberry leave you comment below will back to you as soon as possible