Not possible under the QSA.
Labor and Greens will not support a change so it will not be amended.
Government debt guarantee the most likely outcome."
I would not be so sure.
Labor and the greens may not support it now, but if the Government refuse to use any more tax payers money to prop up a bad investment, and EK want it, the Government should call their bluff and NOT provide any tax payer money or guarantee of, guess what, I reckon the Labor party and the greens would back down.