Can’t evo the same player again or discard an unwanted in progress evolution

I don’t understand why we can’t first of all evo the same player but on different occasions and have 2 variations of the same card evo’d, I also don’t understand why I can’t discard an in-progress evolution which is preventing me start a new and better one on the player, e.g. I applied Oscar to Great guti without looking at the requirements and now I don’t wanna complete him due to a new chain with goal frenzy and rapid wing mastery but because I can’t discard my great guti Oscar or submit him into an sbc, I won’t be able to evo him into the chain as they expire before great guti does and it saddens me, the only person who loses out by discarding the great guti card is me, I lose 65k I used to do the evo, I just don’t understand