Wayne I think yo have posted two questions
re oil/fluid and water if its a very small amount should not matter however its designed to run on power steering fluid and there may be a small risk of corrosion.
As to draining off follow the feed and return pipes from the reservoir and disconnect at lowest point drain off reconnect and refill with correct fluid.
Might be worth asking when you buy replacemnt fluid the cost of getting them to replace on your behalf much easier to do on a ramp.
Maurice
March 2010