Might be able to unplug the compressor clutch and just apply 12 power and a ground. I know they are variable speed but it's worth a try. If it won't work you'll need a recovery machine to pump in the refrigerant charge.
Was the system opened? If it was you need to draw a vacuum on it, you can't just stick a can on it. It won't fill with enough refrigerant before it hits the pressure limit. If you need to just cycle, start car and turn AC on