Dude - what is the extension number of the phone that has Line 06 assigned to it, that you want to make blank so that you can reprogram the button to something else?????????
THAT is the extension number that you dial when you get to the step
"Dial the extension number of the phone you want to remove Line 06 from"
So lets pretend that it is Extension 15 that has the Line 06 button stuck on it.
Go over to Ext. 10 and press the buttons in this order:
Feature, 0, 0, Left Intercom, Left Intercom, #, 3, 0, 1, 1, 5, 0, 6, 2, Feature, 0, 0
Now go back over to Extension 15 and press Feature, 0, 0, and then press the button that Line 06 was previously programmed on.
Does the display say "Blank"? If so, what do you now want to program this blank button to do??