If your pool has an auto-drain then rain will overfill and it will drain some. Splashout will drain some. Buying a cheap utility pump @ Harbor Freight and draining a little bit at a time will help too. A few smaller drains will not risk your pool integrity, but there's a couple considerations.
1. Make sure if it's super hot where you are, keep your plaster wet.
2. When you drain below the skimmer line you might need to make sure your pool pump is off to prevent sucking in air into the return lines. That could overheat pumps possibly depending on your setup.
3. If you have a spa built into your pool, which water is fed into the spa and trickles down to the pool, you can try draining it, as a small container of a few hundred gallons at a time.
Just make sure you're not adding additional CYA with pucks, powered shock, etc, so the problem doesn't increase.
Also, the chem geeks on the site have largely discovered that things like BioActive CYA reducer don't work, waste money, and possibly cause side issues with ammonia.
I was at 220 CYA, did a 50% drain, filled it back up, and let it trickle down from 110 > 60 by a few months of rain overflow drain offs / splash outs.
Hope this helps.
1. Make sure if it's super hot where you are, keep your plaster wet.
2. When you drain below the skimmer line you might need to make sure your pool pump is off to prevent sucking in air into the return lines. That could overheat pumps possibly depending on your setup.
3. If you have a spa built into your pool, which water is fed into the spa and trickles down to the pool, you can try draining it, as a small container of a few hundred gallons at a time.
Just make sure you're not adding additional CYA with pucks, powered shock, etc, so the problem doesn't increase.
Also, the chem geeks on the site have largely discovered that things like BioActive CYA reducer don't work, waste money, and possibly cause side issues with ammonia.
I was at 220 CYA, did a 50% drain, filled it back up, and let it trickle down from 110 > 60 by a few months of rain overflow drain offs / splash outs.
Hope this helps.
So as you pull water from the drain, you can hopefully "push" returned water from a different outlet. If you have a drain from the filter housing, that will work, although some of those outlets are fairly small. You could also try hooking-up a PVC extension/elbow from the return jet(s) to push water from there as well. I have a 2" stub-out from when my pool was built (for a water feature/fountain) so that's my easy water escape/drainage. 
