Removing a specific enchantment from an item in a GUI

I'm trying to make something that takes two items with an Identical level of the Looting Enchant and and making a new item of the same type with 1 level higher of Looting, but at the moment it says the item is enchanted with Looting I and Looting II when combining two Looting I items

Is there any way to remove enchantments from an item, or just getting the type of the item?