Hi @ngoenka I found a solution to make sure you clear their cart first of the items that you are trying to add so that you don’t just increase quantity of items already there (if they view in the same browser). All you need to do is put the variant in your URL twice with the first instance being for 0 quantity.
Add three cases of Soylent Drink Cacao
https://soylent.com/cart/update?updates[8114434703466]=3
Remove any cases of Soylent Drink Cacao from the cart
https://soylent.com/cart/update?updates[8114434703466]=0
Remove any cases of Soylent Drink Cacao from the cart and then add three cases
https://soylent.com/cart/update?updates[8114434703466]=0&updates[8114434703466]=3