If you haven't run the car, you can probably siphon out the reservoir. Otherwise, I'd recommend the DIY power flush method. Below is a reprint of the way I flush/exchange ps fluid from all of my cars. You'll need a helper for this procedure.
1. Disconnect the return line to the reservoir.
2. Drain the reservoir and cap the open connection.
3. Route the return line to a suitable reservoir.
4. Open and line up at least two quarts of new ps fluid for quick pouring.
5. Fill reservoir with new fluid.
(Here comes the fun part

6. Have helper turn engine on, and immediately turn steering wheel from lock to lock, all the while you're pouring fluid into the reservoir.
7. Turn engine off.
8. Reconnect return line to reservoir.
9. Top off fluid.
10. Clean up mess.
Keep in mind the fluid comes out forcefully during flushing. Lifting the front end so the wheels are off the ground helps reduce the flow to a managable level.