Right click Spirit Overflow in your Library, select "Properties"

未标题-1-03.png

Choose "LOCAL FILES" and click "Browse"

未标题-1_画板 1.png

Find "DataFile" and delete it. 

未标题-1-02.png

Launch Spirit Overflow again, you will be able to choose another server (If you change a server, you will have to register your account again )