Hi! If it is some class file then there are several steps
- copy old class file and name it as you want, fix class name in new file and keep it in place you want, recompile source
- open Editor, find all BPs inherited from old class with Audit Assets window (from context menu on assets), switch all of them to inherit from new class
- replace all refs in CPP to new class
- now you can simply delete old file and thats it