Getas >>
星期三 四月 10 - 12:40 I believe at any moment: if you want a developped team, click on the bot team you want and take it over, as long as you already have a "developped" team (Stadium 3+).
Otherwise, if you want a weak team, abandon your team and then choose a new one. Be careful you will only be allowed to choose a very weak team if you abandon your current team first.
Check the guide under "The Basics"...