Once a dub is finished, the source video and its dub are tied together. If you go back and re-cut, re-shoot, or substantially change the source, you can't replace the source on an existing dub — you'd need to start fresh.
Why you can't replace the source
A finished dub is built from many tightly connected pieces:
The transcription of the original audio
Translations into each target language
Voice clones tied to the source speakers
Per-segment timing aligned with the source video
Lip-Sync output keyed to specific frames.
If you replace the source video, all of those become stale. The transcription points at audio that's no longer there. The lip-sync targets faces in frames that are now different. Re-aligning everything to a new source is essentially the same work as creating a new dub.
Small wording change in one or two segments
If your edit was small — fixed a typo in your script, replaced a word, removed a brief mistake — and the audio length is roughly the same, you can fix it inside the existing dub:
Find the affected segment(s) in your existing dub.
Edit the original text or the translated text to match the new content.
Save. The audio regenerates for that segment.
This avoids re-rendering the whole video. See Editing a segment: original text and translation for the specifics.
Substantial re-cut, re-shot footage or new sections
If the source video itself is different (sections cut, new clips added, total length changed):
Upload the new source as a brand-new dub.
Pick the same source and target languages.
Reuse your custom voices, Translation Styles, and glossary if they're configured at the project or account level — the new dub picks them up automatically.
Re-link any external share links (the old dub's link won't show the new content).