If you do tubeless semi tires, you should have access to a bead hammer. One end is like a duck bill and the other is a square maul. Save an empty dishsoap squeeze bottle and mix a 20-30% mix of dishsoap and water. Once you have the tire deflated, lube the tire to ring seat with the dishsoap. Use the slide hammer or bead breaker to loosen the tire from the ring first and then tap the lock ring to disassemble the wheel. Tap on the outer edge. The dishsoap will help them come apart. The tire will most likely be rusted to the outer ring and will need more "encouragement" to come loose.
The lock ring has a notch for the pry bar. Step on the ring to unlock the ridge and start at the notch. The ring ridge is oval shaped to allow it to be pried over the wheel. I have a pic of the pieces but can't post it.
As a side note, if the tires are holding air now and are good enough to put on different wheels, I would leave them alone. They aren't dangerous as they sit. The danger is in inflating them if they aren't locked properly at that time. If the tires are flat now, BE CAREFUL putting air in them to move the truck. The lock has relaxed and could be out of position to re-lock under pressure. I inflate these with 10# and visually check the ring to be certain it is under the wheel lip. Keep adding 10#s at a time and rechecking the lock ring. Some people use 3/8" chains thru the hand holes around the wheel as a safety device if the ring lets go. I've never had a split wheel come apart on me. With constant attention to what the wheel is doing, they can be safely inflated. You can't just lock an inflation nozzle on the stem and walk away like a tubeless.
