Can I change my 2010 OUtback to FWD"
My Outback really slides in winter. I've heard you can change it to FWD? Is
this true and, if so, how do I do it?
Why? That would make things worse. All you need is good winter tires. Try the Nokian's as they are probably the best snow tire there is.
All wheel drive is more secure, who advised you to do this? FOR is correct, just get winter tires and you'll be fine.
The ONLY time bypassing AWD into FWD would be a good idea is as an emergency measure when climbing BACKWARDS (in reverse) up a steep hill, where all the traction and weight transfer would be to the front (now "rear") axle. Lots of snow options, inc the new Conti SI I'm trying on my daughter's modern OB. Stick with 225/60R17 by the way. Michelin X-Ice are nice, too, but pricier. Yoko IceGuard and Dunlop Graspics are a noisier step down. The newer Blizzak WS80 is also a top choice. All are more affordable than Nokian Haks.
Get a set of cables for extreme conditions. Just make sure they are the correct type as Subaru's have very little clearance in the wheel wells.