Opening up a line might open up more issues down the line. Total capacity of power steering isn't that much - a little over a qt according to the fsm . When I do mine I'll just suck out and replenish a few times.
Power Steering Fluid Change
how to bleed powersteering.....
Edit: What about undoing the return hose from the reservoir, connect a length of stiff hose to it, route it to an empty 1 gal container of some sort then start the car up for a few seconds? That will allow the pump itself to empty out the fluid. Running it for a few seconds shouldn't cause any damage?
Something like this method used on the honda -
https://www.youtube.com/watch?v=oWcCXyAALCI