How to override individual product discount price at the time of apply discount code on checkoutpage

Hi,
I have added the discount price of individual product. Suppose customer enter the promo code/discount code in checkout page. Both discount apply to product. So, In this case ignore the discount price of individual product and apply the promo code/discount code discount.

For example:

Product Shirt 15% discount individually.
Price: 2108
Compare at price:2480

Customer have discount code for 20%, then he/she applied on checkout page, Currently, shopify apply the discount to Price of product. So, again discount apply on checkout page. In the checkout page price is 1686.4. How to solve this?