Mine drains enough for me to lift, and rinse out. I actually have a hose attached to it so that I can use the old water on my garden.
I removed the plug, and...
threaded a 3/4 nipple through, then...
I put a #18 o-ring around the nipple, on the inside of the pool, next...
I placed a 3/4 cap over the o-ring and nipple, to keep the water in.  Last step...
I attached a hose on the outside of the nipple to drain the water over the garden.
Finished product.
You have to dig a little area out, underneath the hose attachment. Otherwise, it will kink up. I eventually will be adding a filter, but for now this works.