On bungeecord I can't use commands like changepassword or email on servers other than the auth server (I have separate server for auth that instantly sends player to other world after login). It would be great to have the ability to use that commands at any time from any server.

The solution would be something like a plugin for bungeecord that listens to choosen commands and sends them to auth server as the commands were send by a player (and sends the answer back of course). The other solution would be to have a spigot plugin that does the same thing but for servers it's installed in.

I don't see any alternatives. My players can't change the password at the time. The only alternative I see is to use other plugin for authorization, but I don't know a plugin as powerful as authme.