Changing block texture on client side (with a keybind)

Hey,

I'm a bit bad with MCreator, but I needed a mod for my survival world with my friends. You see, in Minecraft, if you want to wax the already placed copper blocks, it will be hard to really know which one is and which one isn't. So I want to change the not waxed copper texture when I press a keybind (like F3+J or configurable), but it need to be client side cuz I don't want other people to see the texture change everytime someone press the button you know... 

Like I said, I'm really bad with MCreator so sorry if I don't understand everything "you" say.

Thanks for the help, have a nice day :)