can't change players in world permissions after acquiring realms.

I purchased a realm using my buddies world. on his account. I have both accounts info. and have been trying to give myself in-game permissions. I have admin via realm. however, I cant change myself from visitor in-game. Ive been switching between our 2 accounts on both platforms. the in-game permissions don't show up in the pause menu. save for one instance. when I enter the world not using realms but using friends currently playing. I can actually visibly see the permission change button. however, I cant change it. I am at my whits end.