Multiple Part's Property Modification

I have 4 assemblies that need their PartName property modified. I need to change the first 6 digits of the property that is made up of 9 digits, in other words, in a 9 digit property I need to change the first 6 digits only. What would be the best, easiest way to accomplish that in Solidworks 2024. I have found a post that points to macros, but the links no longer work. Any help is appreciated. Thank you!