@3wood
Does .wdp file saved in the same folder as the dwg file to be renamed?
Yes. This is true. It will always be where the dwg file is renamed which is also inside the Project. I just made an example project called file rename and this is how it look like!

The WDP file is in there. I also created a Drawing 1.dwg file which should be inside the .wdp file.

Which it is. Now if I keep creating new drawings for the project. The .wdp file will automatically update adding those drawings. Let me show you. I have created 4 more drawings inside the project and this what the .wdp file looks like now.

What you see is.
===DESC1 attribute ----> Cabinet 1
===DESC2 attribute ----> AC/DC Circuit
===DESC3 attribute ---->
and Drawing
Now when I use the renamefile.lsp routine this happens!

The Drawings are renamed and but the .wdp file say different. Which now I wont be able to open them in AutoCAD Electrical.
I hope this was very clear to you on how the .wdp file works. And by the way Drawing 2 does not rename at all and I don't know why. When I run the routine for single drawing it stills does not rename it. I also deleted Drawing 2 and created it a new Drawing 2 and it still doesn't work. This is what it shows.

It prompts that it renamed it but it actually didn't.
Furthermore, thank you so much for your help!
Best Regards