With one of the power steering lines removed, the power steering fluid drained. It drains slowly, so you might want to take a break.
Note: these hydraulic fittings are not like those used in brake systems. There is an O-ring at the end of each power steering line that should be replaced. Unfortunately, the O-rings are not available from Porsche; at least they are not shown in the Porsche parts catalog. I reused the O-rings, but I was extra careful removing them to inspect them for damage. They were slightly stiff, but a very long way from being brittle.
The original O-rings measured:
ID: 5.60 mm, 0.2205"
OD: 9.13 mm, 0.3595"
CS: 2.00 mm, 0.0790"