Do you play on your cell phone, MAC or PC?
The save folder on your PC is located at: AppData\Roaming\RenPy\LustOdyssey
On Android it is: Android\Data\LustOdyssey
On Android you don't need to uninstall the app, if you install it without uninstalling, a pop up appears saying that it will update.
I don't have an iPhone or Mac, so I don't know.