Reductions on single products

Hi everyone,

I was wondering if there is a way to add a reduction to a product in the cart even if it repeats in the cart. I have a problem where my clients can add multiples of the same product in the cart and I've added a reduction to take 40% off that specific product. The thing is that the reduction only works on one of the products in the cart, even though they added the same product but just multiple times.

How can I fix my problem?

Thanks