Everything

You decide to change almost every single aspect, to what students are allowed, the age limit, lessons, and uniforms. The first and biggest change was that only females would be allowed at the school, making up some reported cases of sexual conduct between students being too much, and they would be allowed back onto campus at a unprecedented date. Then you changed the majority of the classes, including a extended sexual education, removing any unneeded classes such as broom riding and singing. You then change the females uniforms, making the tops tighter and shorter, allowing more skin to be shown, and a shortened skirt, covering up to the bottom of their thighs. You change the age limit to 18 and over, so that the school would be able to keep up with loss funds. Any others would be sent to another school free of charge. You then send out a announcement that Dumbledore will be on a mission to find some Horcruxs, and he will be leaving the headmaster spot in a trusted friend, you. You open up the school soon after these changes, and on opening day a certain student went into your office seeking change