Use UpdateVocabulary with an AWS SDK or CLI

    /// <summary>
    /// Update a custom vocabulary with new values. Update overwrites all existing information.
    /// </summary>
    /// <param name="languageCode">The language code of the vocabulary.</param>
    /// <param name="phrases">Phrases to use in the vocabulary.</param>
    /// <param name="vocabularyName">Name for the vocabulary.</param>
    /// <returns>The state of the custom vocabulary.</returns>
    public async Task<VocabularyState> UpdateCustomVocabulary(LanguageCode languageCode,
        List<string> phrases, string vocabularyName)
    {
        var response = await _amazonTranscribeService.UpdateVocabularyAsync(
            new UpdateVocabularyRequest()
            {
                LanguageCode = languageCode,
                Phrases = phrases,
                VocabularyName = vocabularyName
            });
        return response.VocabularyState;
    }

To update a custom vocabulary with new terms.

The following update-vocabulary example overwrites the terms used to create a custom vocabulary with the new ones that you provide. Prerequisite: to replace the terms in a custom vocabulary, you need a file with new terms.

aws transcribe update-vocabulary \
    --vocabulary-file-uri s3://DOC-EXAMPLE-BUCKET/Amazon-S3-Prefix/custom-vocabulary.txt \
    --vocabulary-name custom-vocabulary \
    --language-code language-code

Output:

{
    "VocabularyName": "custom-vocabulary",
    "LanguageCode": "language",
    "VocabularyState": "PENDING"
}

For more information, see Custom Vocabularies in the Amazon Transcribe Developer Guide.

def update_vocabulary(
    vocabulary_name, language_code, transcribe_client, phrases=None, table_uri=None
):
    """
    Updates an existing custom vocabulary. The entire vocabulary is replaced with
    the contents of the update.

    :param vocabulary_name: The name of the vocabulary to update.
    :param language_code: The language code of the vocabulary.
    :param transcribe_client: The Boto3 Transcribe client.
    :param phrases: A list of comma-separated phrases to include in the vocabulary.
    :param table_uri: A table of phrases and pronunciation hints to include in the
                      vocabulary.
    """
    try:
        vocab_args = {"VocabularyName": vocabulary_name, "LanguageCode": language_code}
        if phrases is not None:
            vocab_args["Phrases"] = phrases
        elif table_uri is not None:
            vocab_args["VocabularyFileUri"] = table_uri
        response = transcribe_client.update_vocabulary(**vocab_args)
        logger.info("Updated custom vocabulary %s.", response["VocabularyName"])
    except ClientError:
        logger.exception("Couldn't update custom vocabulary %s.", vocabulary_name)
        raise