How do I reload a save file (desc)

By DuncanChillo

so i got the part when flowey said "say, I knew somehow to get you a better ending, I did my neutral route with asgore today and blah blah blah. so Idk how to reload it, when I just press continue on the save file it just goes back to the asgore fight. so how do i get the true pacifist ending now? I'm very confused and I need someone to help me. I'm in my files so