Programming Modicon PLC with Unity Platform

I was wondering if there is a way to convert the PLC code sections .XBD into excel, edit them, and reimport them.

You certainly can. You can export as XEF i think it is (or maybe ZEF) which when you open in a text editor looks like an XML file.

I do this when mapping IO from STB remote I/O, and for building my tag database from IO list spreadsheet.

Then just import back in.