Parts editor will do this. The bus definitions are “internal connections” and somewhat complex to change (which is why I usually ignore parts editor in favor of editing the files directly.) These two tutorials should help, Old_Grey’ deals with parts editor mine with editing the files. In either case you are best to run the part through FritzingCheckPart.py (detailed in my tutorial) to both check it is correct and correct things that the svg editors do that Frtizing objects to (such as putting px in font-sizes.)
I lately learned there aren’t links to the videos in Old_Grey’s tutorial so you need to do a google search for the title and then they come up on YouTube.