Changing from “Generic” to “Brand name”

So in creating the original listing I didn’t have the packing with the logo in there or anything so in the Brand I put “Generic”. Now my packaging with the logo and everything is ready and I’d like to change it from “Generic” to my “Brand name” and provide Amazon pictures showing the brand is mine and is being used. It’s not letting me do it for some reason. Does anyone have any advice on this? Do I need to create a new product listing altogether to get this to work with new UPC codes or is there an easier way??