It will either go back here and reform these reactants, or follow this pathway and form these products. So that same histidine then removes the phosphoryl group from the third carbon, forming that rearranged two phosphoglycerate molecules. So that's how this step actually takes place. But the next question is why does this step actually take place? What's the benefit of this step? Well, basically, the reason this step takes place is to make this molecule slightly more reactive.