Character_BP Parent Class won't load, how do I set a new one?

Everytime I try to open one of my Character_BP’s it fails and gives this message
“Blueprint could not be loaded because it derives from an invalid class. Check to make sure the parent class for this blueprint hasn’t been removed!”

I’ve seen the option to add a parent class when you’re in the editor, but I can’t access it, it only gives me this message.

Anyone know what to do to fix this? Would love to be able to fix all my character bp’s.

This means the parent has likely been deleted.
Unless you have a backup of it…

I’ve not found a way to fix this, I’ve had to completely recreate the Character_BPs.