# Retrain Categories

Use the `CategorySetTraining` action to retrain a category. You can use text, documents, a Boolean expression, and category content or a combination of these to retrain a category. When you retrain a category, its original training merges with the new training. For example:

    action=CategorySetTraining&Category=323499876022105571056&Boolean=dog AND NOT cat&BuildNow=True

In this example, the IDOL Category component retrains the category with the ID `323499876022105571056` using the Boolean expression `dog AND NOT cat`. The `BuildNow` parameter instructs Category to build the categories immediately, so that they become active. You can also activate the category at a later point by using the `CategoryBuild` action.

Related Topics

- Build Categories

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