If you have a Porta Power hydraulic spreader–puller, you may be able to attach some chains in various positions on the table and either push or pull the bow or twist out of it. The challenge is that it’s going to spring back as soon as you let off the pressure, so when you get it in position you might need to take some support material like steel tubing and weld it to the table before removing the tension.
The other option is to NOT try to fix the warp but instead work around it. This is what I would actually recommend, because you could damage or weaken the table further by trying to force it back.
So instead, get some thin shim material and build it up by welding it to the surface strategically to create an artificial surface that is indeed flat. So let’s say that the table had warped to a point where the middle is depressed by 1/8”. Lay a long straight edge across the high points and then shim up the low points progressively every 6 inches or so to build them up. As long as you can lay your material across the elevated points, you’ve got no problem! You’re just creating an elevated surface!
You could also do this by simply welding on the surface and building up material. Then once it’s elevated, gently use a flap disc to bring it down until you’ve established a flat plane.