I assume you mean PCV. Having done it recently, I know for sure that the front can't be changed without engine rotation. I didn't do it, but I believe the rear can be changed without engine rotation. At least, I know that you can get the rear PCV valve itself out since I did do that. I assume the grommet could also be taken out as well.
You have to press hard on the rear PCV valve to be able to remove it avoiding the frame and it can lead to PCV valve crack. So I would not recommend to remove PCV valves and gaskets without engine rotation.