how do you edit relationship values?
You export NPC Memories. You can find the file in your AppData\LocalLow\Three Eyes Software\Silverpine folder. Open it with notepad or something, and you can edit relationship scores, there current limit, and other memories an NPC has. Note you can only see the information of an NPC you've met.
Edit: You then have to import the edited file. I forgot to mention that part, but it should be fairly obvious.