A model release is a legal document, and changing information after it has been signed may invalidate the release, so use caution.
If you need to make changes to simple sections, like address and contact information, please feel free to add that information and re-submit the release.
If you need to make changes to any section that alters your specific agreement with the model (i.e. shoot dates or ranges, shoot description, adding nudes), a fresh release should be signed, or both the photographer and model should initial any changes. Stocksy won’t accept such changes without evidence of agreement by the model on the form.