A pinch bar or other heavy lever is the way to get started. (Around here, a breaker bar is a non-ratcheting socket wrench handle.)
You will need a stack of 1/2" hardwood plywood (better) or metal (not so good, slippery) plates
at least 3x3" or 4x4" (6x6" is much better when the stacks get higher), perhaps a comparable stack of 2-3" thick hardwood blocking, a pinch bar, and ideally a toe jack. A second human with enough common sense to keep fingers out from under the machine can also be a real help.
You can possibly use
high-quality softwood plywood, but my limited experience is that it will crush under the machine feet and end of the pinch bar much more readily than the hardwood plywood. Cheap CD plywood with internal voids filled with putty is strictly to be avoided for this procedure! Consider a sheet of hardwood plywood as an investment in your rigging tool kit. BTW, hardwood plywood here means all the plys, not just the wafer-thin veneer on the faces.
Using the pinch bar, raise one side of the machine and slide a plywood plate under each foot on that side. Make sure the foot bears on the center of the plate, not just near an edge (much less just near a corner). Move to the opposite side of the machine and repeat. If that's not high enough to get the toe jack under the edge, put a plywood plate on the floor where you were using the pinch bar and repeat. The machine is now 1" higher off the ground, which should be high enough to get a toe jack under the edge. If you don't have a toe jack, keep raising all the stacks 1/2" at a time, including the fulcrum stacks for the pinch bar.
If you need to protect the finish or surface coating on your floor, put a thin plywood plate under the pinch bar fulcrum even for the first 1/2" raising.
If you have a toe jack, after the machine is high enough, get the fulcrum plates out of the way, and use the toe jack to raise the machine more than 1/2" at a time (don't be reckless and tip it over), and increase the stack height accordingly. Alternate sides until the machine is high enough to get rollers, leveling screws or whatever under it. For convenience in manipulating the stacks and greater piece of mind, you can replace bunches of plywood plates with thicker blocking when the machine gets that high.
Now, if you put the plywood plates squarely under the machine feet, the odds are good the stacks of blocking are going to interfere with whatever you want to do with the machine. Not a major problem. The machine is now at a proper height. Work on one foot at a time. Put two stacks of blocking next to each foot. They will be a bit short. Raise that side/corner of the machine just a little bit. Pull out the original blocking stack and bring the two nearby blocks up to full height and set the machine back down again.
Tony's suggestion of tapping the base holes and jacking it up also works, but the ends of the jack bolts will grind into your floor a little bit. You also need to be prudent about how high you jack it up. Columns under compression will deflect abruptly, when
either the load or the length gets too large. I would treat anything under 3/4" jack bolts like the pinch bar, and continually update the stacks of blocking as you raise the machine. That way, if anything goes wrong, the machine will be caught before it falls or tips very far.