I had this issue with our motorhome. Even though it may not seem like it, it can be turned without cutting anything on rv's from what I have found online.
I used a standard flat pry bar, put the end of it in the groove at an angle, and went to town on it with a hammer until it slowly worked its way to where I needed it.
1992 Dutchmen 30FK
2 adults who don't know they are adults, 3 furry feline children