Guild Wars 2

What exactly does that mean?

You use the skin on an item, you can’t use it on another item.

Ursan.7846:

You use the skin on an item, you can’t use it on another item.

Correct, however if you want to change the stats to a different item and keep the skin, you can always use a Transmutation Stone. The One Time Use only means you won’t have to use a Trans Stone the first time you want to apply it to an item.

Ahhhhhhhkkkkk thank you