What size are the tanks? How old are they? What are your water conditions?
The most important thing is not to let it freeze. If freezing is a risk and you can't store them in a safe location, then remove the valve and drains tanks of water as best you can.
Depending on the size of the softener:
With the remote tank, you can invert it--carefully not to crack any parts--and the water will run out. Then take the remote top and put it on the other tank and do the same. This will get more water than siphoning. The resin will still be wet but at least the tank won't crack. I don't encourage any 'anti-freeze' type solution. If you take the valve off, plug the riser tube so nothing drops into it and cover so animals don't get in (a plastic bag is good). Put the valve in a freeze-proof location.
Over time, a little iron and other contaminants may precipitate and you may have reddish water on start up in the spring. Put it through a regeneration on each side and sanitize while you are doing that.
If freezing is not an issue, then just let it sit and manually regenerate when you start up. Sanitizing is always an option and may need to be considered.