The codes #6051 and #6053 would be entered from your extension to trun off call forwarding codes.

The codes #6052 and #6054 are codes used to turn off another extension's call forwarding, such as if someone from another extension were to cancel call forarding at your extension.

To enter a code, just select your DN key, also refered to as the Intercom key, and enter the codes, starting with the # key. A confirmation tone will tell you that the code was accepted.

This won't disable System call forwarding to voicemail, if this has been setup. This will cancel call forwarding that was activated by using codes such as #6011. If you have a display, it should show you what type of call forwarding is activated.