Hi,
Yeah, that's a bit of workflow problem. It's the same in Unity, you can't really do this, I would guess because it's very dangerous to totally mess your project for good with a single click
Typically, I would take the time to do this manually, because such refactoring is indeed criticial for the stability of any kind of project. We all have to do this kind of stuff at some point, and indeed, I NEVER rely on refactoring options even when it's available. because I want to cover everything with my own moderation.
One way thos is to delete the action itself, so for example if you use "PlayerPrefSetInt" for example, delete the script "PlayerPrefSetInt.cs" and then PlayMaker is going to give you errors on all states that was using this missing action, then you have a more convenient way to go over everything. Once that's done, simply reimport PlayMaker and the action will come back.