Getting a Rp to Lp conversion system and vise versa

so as someone that likes to own a lot of champions and skins i constantly buy rp so i can get them quicker or get a cool skin for a champ i really like to play. But then im usually left with a odd amount of rp where i can not buy anything with it so it just sits there. I dont know if others feel the same way about this as i do but it is really aggravating. I would much rather convert that Rp into lp to possibly get me one more champ. or convert the sum of lp i have into getting a cool skin when i do not feel like going out and buying rp (sense you can only buy skins with rp "something else i think should change"). i think this could help out in more ways then just getting all the champs or skins it can also help players get ride of unwanted rp if they own everything so that they can add to the runes they own so they can have more diverse rune pages without having to go back to the store.