Unless there’s a new trick in newer versions, I think you’ll have to import the new audio, sync it to the picture, then autosync it and create new clips. Then you’ll have to manually cut them (pic & audio) into the edited sequence, replacing the old clips. I use the blue arrow for this sort of thing. That way it fills in both pic and audio nicely when the cuts are not in the same place for both.
Hopefully for you, someone has an easier way to go about this.