you can do it yourself and only yourself. If yous friend does it for you, your insurance will not cover-fire insurance eg.
If you have four wires, disconnect the red one from positive and capped it in the main box and cap the red wire at the other line. Only use the black, white and bare ones.
If you have three wires, change the white wire to the negative.
Leave the black wire as positive, and bare one as neutral.
