You can't. I may do separate versions for the next update
I wish you would! This was one of the first adult VNs I played, before I realized incest patches were a thing (it's one of my few fetishes so I generally prefer having that content enabled), and I really enjoyed it as written. I think it makes a lot more sense having the mom of the household you're staying in just being a friend of your dad. The relationships were fleshed out and given a lot of context and history, and it all worked - it didn't feel like it was a simple "this is your mom and sister but we just did a word swap to landlady and roommate" that you typically find in this type of game. (Except for the scene where you and Jessica are watching anime together, that's a pretty blatant word swap, lol.) The plot is so integral to this game in particular, that I don't want to change it fundamentally by altering the relationships.