This process briefly describe how to delet ITL files from a CISCO Unified IP Phone.
Click on the Settings Button. This will bring the settings menu. Scroll down to Security Configuration.
Select the Trust List menu entry.
Scroll down to the ITL File. Use the unlock sequence on the keypad of the phone. ( * * # ) Star, Star, Pound. The phone will display. Settings Unlocked!.
Select the ITL file.
Click on the more option.
You will be presented with the Erase softkey. Click on the Erase. this will cause the phone to delete the ITL trustlist and have the phone reboot.