Hextech Crafting Skin Shard Reroll
> What happens if I get a skin for a champion that I don’t own?
> If you’re not interested in unlocking that champ, you can re-roll a skin shard with three others for a shard guaranteed to be for a champ you own or you can disenchant the skin shard and use the new essence to craft something that better fits your playstyle (permanent loot disenchants into more essence than shards).
The above is taken from the FAQ regarding Hextech Crafting and Loot; bolded is the section I would like to bring up.
I used the Reroll option on three Skin Shards that I didn't want to redeem; Officer Caitlyn, Definitely Not Blitzcrank, and Uncle Ryze. I wound up getting Vancouver Amumu, which...I don't own Amumu. I don't expect any free re-rolls or anything, I just wanted to bring to Riot's attention that they need to refine the Hextech Crafting's system so that you're guaranteed to not reroll a skin for a champion you don't own.