Edit> Replace in notepad. Now type in the common name you want to replace, In my case its L01 (layer 01), Then the name you wish to replace L01 with. So in my case it's Soil since this is a soil layer. Make sure to press [Replace All]
While Replace is still up you can also do this for the group name, So in my case Layer_01_soil now becomes Soil.
Final Step Copy the nodepad text. Alt+A to highlight all, Alt+C to copy, In Unreal Engine Alt+V to paste. Now check all the names have been correctly replaced.