I would tell you how but unfortunately I completely forgot so I'll just quote what the creator said
"RenPy games have two separate persistent files. The first file is simply found in the folder you dowloaded under „game\saves“ and is called „persistent“.
The other one is under „C:\Users\user\AppData\Roaming\RenPy“ Just select the RenPy folder, find the „DatingSim389“ folder inside of it, and delete the persistent file that one has as well."