real_aurgathor They could conceivably put US labels on coke in Mexico and ship them to the US (before April 2nd)
On US lines, they can just just change the sugar source, and have the first few hundred bottles capped with the normal cap, and then start using the yellow cap once corn syrup is washed out of the line.
That’s missing an important point.
The purpose for the switch is religious, because for many observant Jewish people corn (and other “kitniyot” like beans and rice) are forbidden during the 8 days of Pesach/Passover.
This is especially the case among the growing Orthodox population, and is still followed by many other Jewish people especially of Ashkenazi heritage as opposed to Sephardic.
Anyone doing it for religious reasons pretty much by definition would want the product to be certified by a recognized (eg Orthodox) rabbinical certifying agency (such as the OU—Orthodox Union).
The Rabbis do not do shortcuts for Passover Coca-Cola, nor would you want shortcuts at a Bris (circumcision). 🙂