How to turn off the privacy settings on a sprint iPhone?

When I first got my phone my mom made it impossible to forward calls through sprint. Now we're wondering how to turn it back on because I'm unable to forward calls from my iPhone 4. Any help is appreciated I've tried dialing *72 and then the desired phone number but that didn't work for me.

To turn off Privacy Settings:
- Go to Settings
-Go to General
- Scroll until you see Restrictions
- Click on it and slide the slider to Off