You may have better equipment for your weapon or ring so on when you are no longer in need of your current equipment !

In this case, you have to reset your scroll by spending only 50 gems !

Choose the equipment you want to reset first and if you tap upgrade, there will be shown with a circle-arrow saying reset.

* When you are merging the upgraded equipment, it won't be recovered from your scroll, so make sure to reset it before you use it !